fbpx
Wikipedia

Giant otter

April 26, 2024

The giant otter or giant river otter[4] (Pteronura brasiliensis) is a South American carnivorous mammal. It is the longest member of the weasel family, Mustelidae, a globally successful group of predators, reaching up to 1.8 m (5 ft 11 in). Atypical of mustelids, the giant otter is a social species, with family groups typically supporting three to eight members. The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative. Although generally peaceful, the species is territorial, and aggression has been observed between groups. The giant otter is diurnal, being active exclusively during daylight hours. It is the noisiest otter species, and distinct vocalizations have been documented that indicate alarm, aggression, and reassurance.

Giant otter[1]
Temporal range: 0.13–0 Ma
↓
Late Pleistocene – Holocene
Cuiabá River, Mato Grosso do Sul, Brazil
CITES Appendix I (CITES)[3]
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Genus: Pteronura
Gray, 1837
Species:
P. brasiliensis
Binomial name
Pteronura brasiliensis
(Gmelin, 1788)
Giant otter range

The giant otter ranges across north-central South America; it lives mostly in and along the Amazon River and in the Pantanal. Its distribution has been greatly reduced and is now discontinuous. Decades of poaching for its velvety pelt, peaking in the 1950s and 1960s, considerably diminished population numbers. The species was listed as endangered in 1999 and wild population estimates are typically below 5,000. The Guianas are one of the last real strongholds for the species, which also enjoys modest numbers – and significant protection – in the Peruvian Amazonian basin. It is one of the most endangered mammal species in the Neotropics. Habitat degradation and loss is the greatest current threat. They are also rare in captivity; in 2003, only 60 giant otters were being held.[5]

The giant otter shows a variety of adaptations suitable to an amphibious lifestyle, including exceptionally dense fur, a wing-like tail, and webbed feet. The species prefers freshwater rivers and streams, which are usually seasonally flooded, and may also take to freshwater lakes and springs. It constructs extensive campsites close to feeding areas, clearing large amounts of vegetation. The giant otter subsists almost exclusively on a diet of fish, particularly characins and catfish, but may also eat crabs, turtles, snakes and small caimans.[2] It has no serious natural predators other than humans, although it must compete with other predators, such as the Neotropical otters and various crocodilian species, for food resources.

Name

The giant otter has a handful of other names. In Brazil it is known as ariranha, from the Tupí word ari'raña, meaning water jaguar (Portuguese: onça-d'água).[6] In Spanish, river wolf (Spanish: lobo de río) and water dog (Spanish: perro de agua) are used occasionally (though the latter also refers to several different animals) and may have been more common in the reports of explorers in the 19th and early 20th centuries.[7] All four names are in use in South America, with a number of regional variations. "Giant otter" translates literally as nutria gigante and lontra gigante in Spanish and Portuguese, respectively. Among the Achuar people, they are known as wankanim,[8] among the Sanumá as hadami,[9][10][verification needed] and among the Makushi as turara.[11] The genus name, Pteronura, is derived from the Ancient Greek words πτερόν (pteron, feather or wing) and οὐρά (oura, tail),[12] a reference to its distinctive, wing-like tail.[13]

Taxonomy and evolution

 
Giant otter head from the Museu Paraense Emílio Goeldi research institute

The otters form the subfamily Lutrinae within the mustelids and the giant otter is the only member of the genus Pteronura. Two subspecies are currently recognized by the canonical Mammal Species of the World, P. b. brasiliensis and P. b. paraguensis. Incorrect descriptions of the species have led to multiple synonyms (the latter subspecies is often P. b. paranensis in the literature).[1] P. b. brasiliensis is distributed across the north of the giant otter range, including the Orinoco, Amazon, and Guianas river systems; to the south, P. b. paraguensis has been suggested in Paraguay, Uruguay, southern Brazil, and northern Argentina,[14] although it may be extinct in the last three of these four. The International Union for Conservation of Nature (IUCN) considers the species' presence in Argentina and Uruguay uncertain.[2] In the former, investigation has shown thinly distributed population remnants.[15] P. b. paraguensis is supposedly smaller and more gregarious, with different dentition and skull morphology. Carter and Rosas, however, rejected the subspecific division in 1997, noting the classification had only been validated once, in 1968, and the P. b. paraguensis type specimen was very similar to P. b. brasiliensis.[16] Biologist Nicole Duplaix calls the division of "doubtful value".[17]

The earliest fossil evidence of the giant river otter dates to the Late Pleistocene of Argentina, and it was slightly larger than known modern specimens.[18] An extinct genus, Satherium, is believed to be ancestral to the present species, having migrated to the New World during the Pliocene or early Pleistocene.[13] The giant otter shares the South American continent with three of the four members of the New World otter genus Lontra: the Neotropical river otter, the southern river otter, and the marine otter.[19] (The North American river otter (Lontra canadensis) is the fourth Lontra member.) The giant otter seems to have evolved independently of Lontra in South America, despite the overlap. The smooth-coated otter (Lutrogale perspicillata) of Asia may be its closest extant relative; similar behaviour, vocalizations, and skull morphology have been noted.[13] Both species also show strong pair bonding and paternal engagement in rearing cubs.[20] Giant otter fossil remains have been recovered from a cave in the Brazilian Mato Grosso.[21]

Phylogenetic analysis by Koepfli and Wayne in 1998 found the giant otter has the highest divergence sequences within the otter subfamily, forming a distinct clade that split away 10 to 14 million years ago. They noted that the species may be the basal divergence among the otters or fall outside of them altogether, having split even before other mustelids, such as the ermine, polecat, and mink.[13] Later gene sequencing research on the mustelids, from 2004, places the divergence of the giant otter somewhat later, between five and 11 million years ago; the corresponding phylogenetic tree locates the Lontra divergence first among otter genera, and Pteronura second, although divergence ranges overlap.[22]

Physical characteristics

 
A wild giant otter "periscoping" in Cantão State Park in Brazil, showing its identifying throat marks
 
Skull seen from the side. Short-snouted as usual in mustelids, it has a pronounced sagittal crest, allowing for a very powerful bite in this species.

The giant otter is clearly distinguished from other otters by morphological and behavioural characteristics. It has the greatest body length of any species in the mustelid family, although the sea otter may be heavier. Males are between 1.5 and 1.7 m (4 ft 11 in and 5 ft 7 in) in length from head to tail and females between 1 and 1.5 m (3 ft 3+1⁄2 in and 4 ft 11 in). The animal's well-muscled tail can add a further 70 cm (28 in) to the total body length.[23][24] Early reports of skins and living animals suggested exceptionally large males of up to 2.4 m (7 ft 10+1⁄2 in); intensive hunting likely reduced the occurrence of such massive specimens. Weights are between 26 and 32 kg (57 and 71 lb) for males and 22 and 26 kg (49 and 57 lb) for females.[25] The giant otter has the shortest fur of all otter species; it is typically chocolate brown, but may be reddish or fawn, and appears nearly black when wet.[26] The fur is extremely dense, so much so that water cannot penetrate to the skin.[27] Guard hairs trap water and keep the inner fur dry; the guard hairs are approximately 8 millimetres (one-third of an inch) in length, about twice as long as the fur of the inner coat.[28] Its velvety feel makes the animal highly sought after by fur traders and has contributed to its decline.[29] Unique markings of white or cream fur color the throat and under the chin, allow individuals to be identified from birth.[26]

Giant otter muzzles are short and sloping and give the head a ball-shaped appearance.[17] The ears are small and rounded.[27] The nose (or rhinarium) is completely covered in fur, with only the two slit-like nostrils visible. The giant otter's highly sensitive whiskers (vibrissae) allow the animal to track changes in water pressure and currents, which aids in detecting prey.[30] The legs are short and stubby and end in large webbed feet tipped with sharp claws. Well suited for an aquatic life, it can close its ears and nose while underwater.[31]

At the time of Carter and Rosas's writing, vision had not been directly studied, but field observations show the animal primarily hunts by sight; above water, it is able to recognize observers at great distances. The fact that it is exclusively active during the day further suggests its eyesight should be strong, to aid in hunting and predator avoidance. In other otter species, vision is generally normal or slightly myopic, both on land and in water. The giant otter's hearing is acute and its sense of smell is excellent.[26][32]

The species possesses 2n = 38 chromosomes.[33]

Biology and behaviour

The giant otter is large, gregarious, and diurnal. Early travelers' reports describe noisy groups surrounding explorers' boats, but little scientific information was available on the species until Duplaix's groundbreaking work in the late 1970s.[34] Concern over this endangered species has since generated a body of research.

Vocalizations

The giant otter is an especially noisy animal, with a complex repertoire of vocalizations. All otters produce vocalizations, but by frequency and volume, the giant otter may be the most vocal.[35] Duplaix identified nine distinct sounds, with further subdivisions possible, depending on context. Quick hah barks or explosive snorts suggest immediate interest and possible danger. A wavering scream may be used in bluff charges against intruders, while a low growl is used for aggressive warning. Hums and coos are more reassuring within the group. Whistles may be used as advance warning of nonhostile intent between groups, although evidence is limited. Newborn pups squeak to elicit attention, while older young whine and wail when they begin to participate in group activities.[36] An analysis published in 2014 cataloged 22 distinct types of vocalization in adults and 11 in neonates.[37] Each family of otters was shown to have its own unique audio signature.[38]

Social structure

The giant otter is a highly social animal and lives in extended family groups. Group sizes are anywhere from two to 20 members, but likely average between three and eight.[14] (Larger figures may reflect two or three family groups temporarily feeding together.)[39]

 
Giant otters leave a pool together at the Philadelphia Zoo. The species is extremely social, a rarity among mustelids, and family groups are cohesive.

Group members share roles, structured around the dominant breeding pair. The species is territorial, with groups marking their ranges with latrines, gland secretions, and vocalizations.[40] At least one case of a change in alpha relationship has been reported, with a new male taking over the role; the mechanics of the transition were not determined.[41] Duplaix suggests a division between "residents", who are established within groups and territories, and nomadic and solitary "transients"; the categories do not seem rigid, and both may be a normal part of the giant otter life cycle.[42] One tentative theory for the development of sociality in mustelids is that locally abundant but unpredictably dispersed prey causes groups to form.[43]

Aggression within the species ("intraspecific" conflict) has been documented. Defence against intruding animals appears to be cooperative: while adult males typically lead in aggressive encounters, cases of alpha females guarding groups have been reported.[41] One fight was directly observed in the Brazilian Pantanal in which three animals violently engaged a single individual near a range boundary.[40] In another instance in Brazil, a carcass was found with clear indications of violent assault by other otters, including bites to the snout and genitals, an attack pattern similar to that exhibited by captive animals.[44] While not rare among large predators in general, intraspecific aggression is uncommon among otter species; Ribas and Mourão suggest a correlation to the animal's sociability, which is also rare among other otters.[40] A capacity for aggressive behavior should not be overstated with the giant otter. Researchers emphasize that even between groups, conflict avoidance is generally adopted.[45][46] Within groups, the animals are extremely peaceful and cooperative. Group hierarchies are not rigid and the animals easily share roles.[47]

Reproduction and life cycle

 
A giant otter den dug on a lakeshore at Cantão State Park – the newly dug white sand is a sign of recent activity at this den.

Giant otters build dens, which are holes dug into riverbanks, usually with multiple entrances and multiple chambers inside. They give birth within these dens during the dry season. In Cantão State Park, otters dig their reproductive dens on the shores of oxbow lakes starting around July, when waters are already quite low. They give birth between August and September, and the young pups emerge for the first time in October and November, which are the months of lowest water when fish concentrations in the dwindling lakes and channels are at their peak. This makes it easier for the adults to catch enough fish for the growing young, and for the pups to learn how to catch fish. The entire group, including nonreproductive adults, which are usually older siblings to that year's pups, collaborates to catch enough fish for the young.[48]

Details of giant otter reproduction and life cycle are scarce, and captive animals have provided much of the information. Females appear to give birth year round, although in the wild, births may peak during the dry season. The estrous cycle is 21 days, with females receptive to sexual advances between three and 10 days.[49] Study of captive specimens has found only males initiate copulation.[5] At Tierpark Hagenbeck in Germany, long-term pair bonding and individualized mate selection were seen, with copulation most frequently taking place in water.[50] Females have a gestation period of 65 to 70 days, giving birth to one to five pups, with an average of two.[49][50] Research over five years on a breeding pair at the Cali Zoo in Colombia found the average interval between litters was six to seven months, but as short as 77 days when the previous litter did not survive.[5] Other sources have found greater intervals, with as long as 21 to 33 months suggested for otters in the wild.[49]

 
Captive giant otters have contributed greatly to scientific knowledge of the species by providing readily available subjects for research on the species' reproduction and life cycle.

Mothers give birth to furred and blind cubs in an underground den near the river shore and fishing sites.[51] Males actively participate in rearing cubs and family cohesion is strong;[52] older, juvenile siblings also participate in rearing, although in the weeks immediately after birth, they may temporarily leave the group.[49] Pups open their eyes in their fourth week, begin walking in their fifth, and are able to swim confidently between 12 and 14 weeks old.[5] They are weaned by nine months and begin hunting successfully soon after.[49] The animal reaches sexual maturity at about two years of age and both male and female pups leave the group permanently after two to three years.[49][50] They then search for new territory to begin a family of their own.[53]

Studies of giant otters in captivity have given indications about the environment necessary to both maintain a physically and behaviorally healthy population and allow successful cub-rearing. These include providing at least the minimum recommended land-to-water area ratio, and that all enclosure land surfaces (both artificial and natural) are nearly entirely covered with the recommended substrate conditions (e.g. tree-bark mulch and soft pebble-free sand/soil). Ensuring that the animals have sufficient privacy from human disturbances (visual and acoustic, from zoo staff or visitors) at parturition and during cub-rearing is also essential, but not sufficient. Insufficient land area proportions and unsuitable substrate conditions in zoos have historically been the primary cause of high cub mortality and physical and behavioral health problems among giant otters. For example, stress to the parents during cub-rearing due to inappropriate enclosure conditions has been the primary reason for cub neglect, abuse and infanticide.[53][54][55]

In the wild, it has been suggested, although not systematically confirmed, that tourists cause similar stresses: disrupted lactation and denning, reduced hunting, and habitat abandonment are all risks.[53] This sensitivity is matched by a strong protectiveness towards the young. All group members may aggressively charge intruders, including boats with humans in them.[56]

The longest documented giant otter lifespan in the wild is eight years. In captivity, this may increase to 17, with an unconfirmed record of 19. The animal is susceptible to a variety of diseases, including canine parvovirus. Parasites, such as the larvae of flies and a variety of intestinal worms, also afflict the giant otter.[53] Other causes of death include accidents, gastroenteritis, infanticide, and epileptic seizures.[49]

Hunting and diet

 
A captive giant otter, when feeding, grasps prey in its forepaws and begins eating immediately, at the head.

The giant otter is an apex predator, and its population status reflects the overall health of riverine ecosystems.[57] It feeds mainly on fish, including cichlids, perch, characins (such as piranha), and catfish.[58] One full-year study of giant otter scats in Amazonian Brazil found fish present in all fecal samples. Fish from the order Perciformes, particularly cichlids and perch, were seen in 97% of scats, and Characiformes, such as characins, in 86%. Fish remains were of medium-sized species that seem to prefer relatively shallow water, to the advantage of the visually oriented giant otter. Prey species found were also sedentary, generally swimming only short distances, which may aid the giant otter in predation.[59] Hunting in shallow water has also been found to be more rewarding, with water depth less than 0.6 metres (2.0 ft) having the highest success rate.[60] The giant otter seems to be opportunistic, taking whatever species are most locally abundant.[59] If fish are unavailable, it will also take crabs, snakes, and even small caimans and anacondas.[61]

The species can hunt singly, in pairs, and in groups, relying on sharp eyesight to locate prey.[62] In some cases, supposed cooperative hunting may be incidental, a result of group members fishing individually in close proximity; truly coordinated hunting may only occur where the prey cannot be taken by a single giant otter, such as with small anacondas and juvenile black caiman.[46] The giant otter seems to prefer prey fish that are generally immobile on river bottoms in clear water. Prey chase is rapid and tumultuous, with lunges and twists through the shallows and few missed targets. The otter can attack from both above and below, swiveling at the last instant to clamp the prey in its jaws. Giant otters catch their own food and consume it immediately; they grasp the fish firmly between the forepaws and begin eating noisily at the head.[62] Carter and Rosas have found captive adult animals consume around 10% of their body weight daily—about 3 kilograms (7 lb), in keeping with findings in the wild.[63]

Ecology

Habitat

The species is amphibious, although primarily terrestrial.[64] It occurs in freshwater rivers and streams, which generally flood seasonally. Other water habitats include freshwater springs and permanent freshwater lakes.[2] Four specific vegetation types occur on one important creek in Suriname: riverbank high forest, floodable mixed marsh and high swamp forest, floodable low marsh forest, and grass islands and floating meadows within open areas of the creek itself.[64] Duplaix identified two critical factors in habitat selection: food abundance, which appears to positively correlate to shallow water, and low sloping banks with good cover and easy access to preferred water types. The giant otter seems to choose clear, black waters with rocky or sandy bottoms over silty, saline, and white waters.[65]

 
A group of four giant otters emerging from the water to patrol a campsite on the riverbank at Cantão State Park

Giant otters use areas beside rivers for building dens, campsites, and latrines.[66] They clear significant amounts of vegetation while building their campsites. One report suggests maximum areas 28 m (92 ft) long and 15 m (49 ft) wide, well-marked by scent glands, urine, and feces to signal territory.[19] Carter and Rosas found average areas a third this size. Giant otters adopt communal latrines beside campsites, and dig dens with a handful of entrances, typically under root systems or fallen trees. One report found between three and eight campsites, clustered around feeding areas. In seasonally flooded areas, the giant otter may abandon campsites during the wet season, dispersing to flooded forests in search of prey.[67] Giant otters may adopt preferred locations perennially, often on high ground. These can become quite extensive, including "backdoor" exits into forests and swamps, away from the water.[64] Otters do not visit or mark every site daily, but usually patrol all of them, often by a pair of otters in the morning.[68]

Research generally takes place in the dry season and an understanding of the species' overall habitat use remains partial. An analysis of dry season range size for three otter groups in Ecuador found areas between 0.45 and 2.79 square kilometres (0.17 and 1.08 sq mi). Utreras[66] presumed habitat requirements and availability would differ dramatically in the rainy season: estimating range sizes of 1.98 to as much as 19.55 square kilometres (0.76 to 7.55 sq miles) for the groups. Other researchers suggest approximately 7 square kilometres (2.7 sq mi) and note a strong inverse correlation between sociality and home range size; the highly social giant otter has smaller home range sizes than would be expected for a species of its mass.[43] Population densities varied with a high of 1.2/km2 (3.1/sq mi) reported in Suriname and with a low of 0.154/km2 (0.40/sq mi) found in Guyana.[14]

In 2021, conservationists at Fundación Rewilding spotted a wild giant otter swimming in the Bermejo River in Impenetrable National Park, located in the Chaco province of northeast Argentina.[69]

Predation and competition

 
Characins such as piranha species are prey for the giant otter, but these aggressive fish may also pose a danger. Duplaix speculated that piranhas may attack giant otters.

Adult giant otters living in family groups have no known serious natural predators; however, there are some accounts of black caimans in Peru and yacare caimans in the Pantanal preying on giant otters.[63] In addition, solitary animals and young may be vulnerable to attacks by the jaguar, cougar, and anaconda, but this is based on historical reports, not direct observation.[70] Pups are more vulnerable, and may be taken by caiman and other large predators,[53] although adults are constantly mindful of stray young, and will harass and fight off possible predators. When in the water, the giant otter faces danger from animals not strictly preying upon it: the electric eel and stingray are potentially deadly if stumbled upon, and piranha may be capable of at least taking bites out of a giant otter, as evidenced by scarring on individuals.[71]

Even if without direct predation, the giant otter must still compete with other predators for food resources. Duplaix documented interaction with the Neotropical otter.[72] While the two species are sympatric (with overlapping ranges) during certain seasons, there appeared to be no serious conflict. The smaller neotropical otter is far more shy, less noisy, and less social; at about a third the weight of the giant otter, it is more vulnerable to predation, hence, a lack of conspicuousness is to its advantage. The neotropical otter is active during twilight and darkness, reducing the likelihood of conflict with the diurnal giant otter.[73] Its smaller prey, different denning habits, and different preferred water types also reduce interaction.[63]

Other species that prey upon similar food resources include the caimans and large fish that are themselves piscivores. Gymnotids, such as the electric eel, and the large silurid catfish are among aquatic competitors. Two river dolphins, the tucuxi and Amazon river dolphin, might potentially compete with the giant otter, but different spatial use and dietary preferences suggest minimal overlap.[63] Furthermore, Defler observed associations between giant otters and the Amazon river dolphins, and suggested that dolphins may benefit by fish fleeing from the otters.[63] The spectacled caiman is another potential competitor, but Duplaix found no conflict with the species in Suriname.[74]

Conservation status

The IUCN listed the giant otter as "endangered" in 1999; it had been considered "vulnerable" under all previous listings from 1982 when sufficient data had first become available. It is regulated internationally under Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) meaning commercial trade in specimens (including parts and derivatives) is prohibited.[75]

Threats

The animal faces a variety of critical threats. Poaching has long been a problem. Statistics show between 1959 and 1969 Amazonian Brazil alone accounted for 1,000 to 3,000 pelts annually. The species was so thoroughly decimated, the number dropped to just 12 in 1971. The implementation of CITES in 1973 finally brought about significant hunting reductions,[14] although demand did not disappear entirely: in the 1980s, pelt prices were as high as US$250 on the European market. The threat has been exacerbated by the otters' relative fearlessness and tendency to approach human beings. They are extremely easy to hunt, being active through the day and highly inquisitive.[76] The animal's relatively late sexual maturity and complex social life makes hunting especially disastrous.[14][77][78]

More recently, habitat destruction and degradation have become the principal dangers, and a further reduction of 50% is expected in giant otter numbers within the 25 years after 2020 (about the span of three generations of giant otters).[2] Typically, loggers first move into rainforest, clearing the vegetation along riverbanks. Farmers follow, creating depleted soil and disrupted habitats. As human activity expands, giant otter home ranges become increasingly isolated. Subadults leaving in search of new territory find it impossible to set up family groups.[79] Specific threats from human industry include unsustainable mahogany logging in parts of the giant otter range,[76] and concentrations of mercury in its diet of fish, a byproduct of gold mining.[80][81]

Other threats to the giant otter include conflict with fishermen, who often view the species as a nuisance (see below). Ecotourism also presents challenges: while it raises money and awareness for the animals, by its nature it also increases human effect on the species, both through associated development and direct disturbances in the field.[79] A number of restrictions on land use and human intrusion are required to properly maintain wild populations. Schenck et al., who undertook extensive fieldwork in Peru in the 1990s, suggest specific "no-go" zones where the species is most frequently observed, offset by observation towers and platforms to allow viewing. Limits on the number of tourists at any one time, fishing prohibitions, and a minimum safe distance of 50 metres (164 ft) are proposed to offer further protection.[82]

Distribution and population

 
Giant otter from Venezuela

The giant otter has lost as much as 80% of its South American range.[76] While still present in a number of north-central countries, giant otter populations are under considerable stress. The IUCN lists Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, and Venezuela as current range countries.[2] Given local extinctions, the species' range has become discontinuous.[14] Total population numbers are difficult to estimate.[2] Populations in Bolivia were once widespread but the country became a "black spot" on distribution maps after poaching between the 1940s and 1970s; a relatively healthy, but still small, population of 350 was estimated in the country in 2002.[39] The species has likely been extirpated from southern Brazil, but in the west of the country, decreased hunting pressure in the critical Pantanal has led to very successful recolonization; an estimate suggests 1,000 or more animals in the region.[76][83]

 
The Guianas are the last real stronghold of the giant otter. Suriname retains extensive forest cover and many protected areas; it is pictured above. Guyana is immediately to the west and French Guiana is immediately to the east.

As of 2020, the IUCN estimates that there may be 4,569 otters living in Brazil.[2] A significant population lives in the wetlands of the central Araguaia River, and in particular within Cantão State Park, which, with its 843 oxbow lakes and extensive flooded forests and marshlands, is one of the best habitat patches for this species in Brazil.[48]

Suriname still has significant forest cover and an extensive system of protected areas, much of which protects the giant otter.[84] Duplaix returned to the country in 2000 and found the giant otter still present on the Kaburi Creek, a "jewel" of biodiversity, although increased human presence and land use suggests, sooner or later, the species may not be able to find suitable habitat for campsites.[85] In a report for World Wildlife Fund in 2002, Duplaix was emphatic about the importance of Suriname and the other Guianas:[64]

The three Guianas remain the last stronghold of giant otters in South America, with pristine giant otter habitat on some rivers and good giant otter densities overall—still, but for how long? The survival of the giant otter populations in the Guianas is essential to the survival of this endangered species in South America.

Other countries have taken a lead in designating protected areas in South America. In 2004, Peru created one of the largest conservation areas in the world, Alto Purús National Park, with an area similar in size to Belgium. The park harbors many endangered plants and animals, including the giant otter, and holds the world record for mammal diversity.[86][87] Bolivia designated wetlands larger than the size of Switzerland as a freshwater protected area in 2001; these are also home to the giant otter.[88]

Interactions with indigenous peoples

Throughout its range, the giant otter interacts with indigenous groups, who often practice traditional hunting and fishing. A study of five indigenous communities in Colombia suggests native attitudes toward the animal are a threat: the otters are often viewed as a nuisance that interferes with fishing, and are sometimes killed. Even when told of the importance of the species to ecosystems and the danger of extinction, interviewees showed little interest in continuing to coexist with the species. Schoolchildren, however, had a more positive impression of the animal.[89]

In Suriname, the giant otter is not a traditional prey species for human hunters, which affords some protection.[85] (One researcher has suggested the giant otter is hunted only in desperation due to its horrible taste.)[79] The animal sometimes drowns in nets set across rivers and machete attacks by fishermen have been noted, according to Duplaix, but "tolerance is the rule" in Suriname.[71] One difference in behavior was seen in the country in 2002: the normally inquisitive giant otters showed "active avoidance behavior with visible panic" when boats appeared. Logging, hunting, and pup seizure may have led groups to be far more wary of human activity.[64]

Local people sometimes take pups for the exotic pet trade or as pets for themselves, but the animal rapidly grows to become unmanageable.[79] Duplaix relates the story of an Arawak Indian who took two pups from their parents. While revealing of the affection held for the animals, the seizure was a profound blow to the breeding pair, which went on to lose their territory to competitors.[71]

The species has also appeared in the folklore of the region. It plays an important role in the mythology of the Achuar people, where giant otters are seen as a form of the tsunki, or water spirits: they are a sort of "water people" who feed on fish. They appear in a fish poisoning legend where they assist a man who has wasted his sexual energy, creating the anacondas of the world from his distressed and extended genitals.[8]

The Bororó people have a legend on the origin of tobacco smoking: those who used the leaf improperly by swallowing it were punished by being transformed into giant otters; the Bororo also associate the giant otter with fish and with fire.[90] A Ticuna legend has it that the giant otter exchanged places with the jaguar: the story says jaguar formerly lived in the water and the giant otter came to the land only to eat.[91] The indigenous Kichwa peoples from Amazonian Peru believed in a world of water where Yaku runa reigned as mother of the water and was charged with caring for fish and animals. Giant otters served as Yaku runa's canoes.[92] A Maxacali creation story suggests that the practice of otter fishing may have been prevalent in the past.[93]

Notes

  1. ^ a b Wozencraft, W. C. (2005). "Order Carnivora". In Wilson, D. E.; Reeder, D. M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 605. ISBN 978-0-8018-8221-0. OCLC 62265494.
  2. ^ a b c d e f g h Groenendijk, J.; Leuchtenberger, C.; Marmontel, M.; Van Damme, P.; Wallace, R.; Schenck, C. (2022) [amended version of 2021 assessment]. "Pteronura brasiliensis". IUCN Red List of Threatened Species. 2022: e.T18711A222719180. doi:10.2305/IUCN.UK.2022-2.RLTS.T18711A222719180.en. Retrieved 10 September 2023.
  3. ^ "Appendices | CITES". cites.org. Retrieved 14 January 2022.
  4. ^ . National Geographic Society. 10 March 2011. Archived from the original on 12 January 2010. Retrieved 6 August 2016.
  5. ^ a b c d Londoño, G. Corredor; Muñoz, N. Tigreros (2006). "Reproduction, behaviour and biology of the Giant river otter (Pteronura brasiliensis) at Cali Zoo". International Zoo Yearbook. 40: 360–371. doi:10.1111/j.1748-1090.2006.00360.x.
  6. ^ Ferreira, A. B. H. (1986). Novo Dicionário da Língua Portuguesa (2nd ed.). Nova Fronteira. p. 163.
  7. ^ See e.g., Duplaix 1980, p. 547
  8. ^ a b Descola, Philippe (1994). In the Society of Nature: A Native Ecology in Amazonia. Cambridge University Press. pp. 280–282. ISBN 978-0-521-41103-5.
  9. ^ Ramos, Alcida Rita (1995). Sanuma Memories: Yanomami Ethnography in Times of Crisis. University of Wisconsin Press. p. 219. ISBN 978-0-299-14654-2.
  10. ^ "none", Antropológica. 1981–1982, volume 55–58, page 107
  11. ^ "Mammals of Iwokrama". iwokrama.org. Retrieved 6 February 2023.
  12. ^ Liddell, Henry George & Robert Scott (1980). A Greek-English Lexicon (Abridged ed.). United Kingdom: Oxford University Press. ISBN 978-0-19-910207-5.
  13. ^ a b c d Koepfli, K.-P; Wayne, R.K. (December 1998). "Phylogenetic relationships of otters (Carnivora: Mustelidae) based on mitochondrial cytochrome b sequences". Journal of Zoology. 246 (4): 401–416. doi:10.1111/j.1469-7998.1998.tb00172.x.
  14. ^ a b c d e f . Carnivores. Food and agricultural organization of the United Nations. Archived from the original on 27 November 2007. Retrieved 7 November 2007.
  15. ^ Chehebar, C. (February 1991). "Searching for the Giant Otter in Northeastern Argentina". IUCN Otter Specialist Group Bulletin. 6 (1): 17–18. Retrieved 6 November 2007.
  16. ^ Carter & Rosas 1998, p. 4
  17. ^ a b Duplaix 1980, p. 511
  18. ^ Prevosti, Francisco J.; Ferrero, Brenda S. (2008). "A Pleistocene giant river otter from Argentina: remarks on the fossil record and phylogenetic analysis". Journal of Vertebrate Paleontology. 28 (4): 1171–1181. Bibcode:2008JVPal..28.1171P. doi:10.1671/0272-4634-28.4.1171. hdl:11336/80190.
  19. ^ a b Foster-Turley, Pat; Macdonald, Sheila; Mason, Chris, eds. (1990). . IUCN/SSC Otter Specialist Group: Sections 2 and 12. Archived from the original on 5 January 2008. Retrieved 21 November 2007.
  20. ^ Duplaix 1980, p. 614
  21. ^ Cartelle, Cástor; Hirooka, Suzana (September 2005). "Primeiro Registro Pleistocênico de Pteronura brasiliensis (Gmelin, 1788) (Carnivora, Mustelidae)". Research Gate. Arquivos do Museu Nacional, Rio de Janeiro Publishing. Retrieved 9 October 2018.
  22. ^ Marmi, Josep; Lopez-Giraldez, Juan F.; Domingo-Roura, Xavier (November 2004). "Phylogeny, evolutionary history and taxonomy of the Mustelidae based on sequences of the cytochrome b gene and a complex repetitive flanking region". Zoologica Scripta. 33 (6): 481–499. doi:10.1111/j.0300-3256.2004.00165.x. S2CID 85818256.
  23. ^ . The Nature Conservancy. Archived from the original on 25 May 2009. Retrieved 25 January 2008.
  24. ^ Boitani, Luigi, Simon & Schuster's Guide to Mammals. Simon & Schuster/Touchstone Books (1984), ISBN 978-0-671-42805-1
  25. ^ Duplaix 1980
  26. ^ a b c Carter & Rosas 1998, p. 2
  27. ^ a b . Meet Our Animals. Philadelphia Zoo. Archived from the original on 11 April 2013. Retrieved 6 November 2007.
  28. ^ . Anheuser-Busch Adventure Parks. Archived from the original on 2 November 2007. Retrieved 6 November 2007.
  29. ^ "Giant Otter Facts". Meet Our Animals. Earth's Endangered Creatures. Retrieved 7 November 2007.
  30. ^ . World Wildlife Fund. Archived from the original on 24 October 2007. Retrieved 19 January 2008.
  31. ^ . Iwokrama International Centre for Rainforest Conservation and Development. Archived from the original on 17 October 2007. Retrieved 7 November 2007.
  32. ^ Duplaix 1980, p. 533
  33. ^ Franco-de-Sá, J. F. O.; Rosas, F. C. W.; Feldberg, E. (2007). "Cytogenetic study of the giant otter Pteronura brasiliensis Zimmermann 1780 (Carnivora, Mustelidae, Lutrinae)". Genetics and Molecular Biology. 30 (4): 1093–1096. doi:10.1590/S1415-47572007000600011.
  34. ^ Duplaix 1980, p. 497
  35. ^ (PDF). Seaworld. 2005. Archived from the original (PDF) on 15 July 2008. Retrieved 23 January 2008.
  36. ^ Duplaix 1980, pp. 552–561
  37. ^ Mumm, C. A. S.; Knörnschild, M. (12 November 2014). "The Vocal Repertoire of Adult and Neonate Giant Otters (Pteronura brasiliensis)". PLOS ONE. 9 (11): e112562. Bibcode:2014PLoSO...9k2562M. doi:10.1371/journal.pone.0112562. PMC 4229255. PMID 25391142.
  38. ^ Mumm, C. A.; Knörnschild, M. (2017). "Territorial choruses of giant otter groups (Pteronura brasiliensis) encode information on group identity". PLOS ONE. 12 (10): e0185733. Bibcode:2017PLoSO..1285733M. doi:10.1371/journal.pone.0185733. PMC 5638252. PMID 29023545.
  39. ^ a b van Damme, Paul; Wallace, Rob; Swaenepoel, Karen; Painter, Lillian; Ten, Silvia; Taber, Andrew; et al. (October 2002). "Distribution and Population Status of the Giant Otter Pteronura brasiliensis in Bolivia". IUCN Otter Specialist Group Bulletin. 19 (2): 87–96. Retrieved 5 November 2007.
  40. ^ a b c Ribas, Carolina; Mourão, Guilherme (January 2005). "Intraspecific Agonism between Giant Otter Groups". IUCN Otter Specialist Group Bulletin. 21 (2): 89–93. Retrieved 7 November 2007.
  41. ^ a b Evangelista, Emanuela (July 2004). "Change of Partners in a Giant Otter Alpha Couple". IUCN Otter Specialist Group Bulletin. 21 (1): 47–51. Retrieved 7 November 2007.
  42. ^ Duplaix 1980, pp. 571–2
  43. ^ a b Johnson, Dominic D.P.; MacDonald, David W.; Dickman, Amy J. (2000). (PDF). Mammal Review. 30 (3&4): 171–196. doi:10.1046/j.1365-2907.2000.00066.x. Archived from the original (PDF) on 19 September 2006. Retrieved 7 November 2007. See figure three for home range size estimate.
  44. ^ Rosas, F.C.W.; De Mattos, G.E. (October 2003). "Natural Deaths of Giant Otters (Pteronura brasiliensis) In Balbina Hydroelectric Lake, Amazonas, Brazil". IUCN Otter Specialist Group Bulletin. 20 (2): 62–64. Retrieved 7 November 2007.
  45. ^ Duplaix 1980, p. 563
  46. ^ a b Carter & Rosas 1998, p. 15
  47. ^ Schenck, C.; Staib, E. (April 1992). "Giant Otters in Peru". IUCN Otter Specialist Group Bulletin. 7: 24–26. Retrieved 22 January 2008.
  48. ^ a b . Instituto Araguaia. Archived from the original on 26 June 2017. Retrieved 10 March 2011.
  49. ^ a b c d e f g Carter & Rosas 1998, p. 18
  50. ^ a b c Hagenbeck, Carl; Wunnemann, Claus (1992). "Breeding the giant otter (Pteronura brasiliensis) at Carl Hagenbecks Tierpark". International Zoo Yearbook. 32: 240–245. doi:10.1111/j.1748-1090.1991.tb02392.x.
  51. ^ Duplaix 1980, p. 567
  52. ^ Duplaix 1980, p. 576
  53. ^ a b c d e Sykes-Gatz, S. (2005). International Giant Otter Studbook Husbandry and Management Information and Guidelines (Second ed.). Germany: Zoologischer Garten Dortmund. p. 13.
  54. ^ Sykes-Gatz, S.; Gatz, V. (2011). International Studbook for the Giant Otter (Pteronura brasiliensis) (Gray 1867) (2nd ed.). Germany: Zoologischer Garten Dortmund.
  55. ^ Gatz, V.; Sykes-Gatz, S. Giant Otter EEP Annual Report 2003, 2007, 2010 (Report). EAZA Yearbook 2003, 2007, 2010. Amsterdam: EAZA Executive Office (European Association of Zoos and Aquariums).
  56. ^ Duplaix 1980, pp. 564–5, 570
  57. ^ Barnett, Adrian; Shapley, Rebecca; Lehman, Shawn; Henry, Everton; Benjamin, Paul (October 2000). "Records of the Giant Otter, Pteronura brasiliensis, from Guyana" (PDF). IUCN Otter Specialist Group Bulletin. 17 (2): 65–74. Retrieved 10 September 2023 – via rebeccashapley.com.
  58. ^ Bender, Jamie. "Pteronura brasiliensis (giant otter)". Animal Diversity Web.
  59. ^ a b Rosas, Fernando C.W.; Zuanon, Jansen A.S.; Carter, Sarah K. (September 1999). "Feeding Ecology of the Giant Otter, Pteronura brasiliensis". Biotropica. 31 (3): 502–506. Bibcode:1999Biotr..31..502R. doi:10.1111/j.1744-7429.1999.tb00393.x. S2CID 86658847.
  60. ^ Carter & Rosas 1998, p. 16
  61. ^ . International Otter Survival Fund. Archived from the original on 11 October 2007. Retrieved 21 November 2007.
  62. ^ a b Duplaix 1980, pp. 544–6
  63. ^ a b c d e Carter & Rosas 1998, p. 17
  64. ^ a b c d e Duplaix, Nicole (2002). Guianas Rapid River Bio-assessments and Giant Otter Conservation Project (PDF) (Report). World Wildlife Fund.
  65. ^ Duplaix 1980, pp. 514–5
  66. ^ a b Utreras B., V.; Suárez R., E.; Zapata-Ríos, G.; Lasso, G.; Pinos, L. (July–December 2005). "Dry and Rainy Season Estimations of Giant Otter, Pteronura brasiliensis, Home-Range in the Yasuní National Park, Ecuador" (PDF). The Latin American Journal of Aquatic Mammals. 4 (2): 191–194. doi:10.5597/lajam00085. Retrieved 7 November 2007.
  67. ^ Carter & Rosas 1998, p. 13
  68. ^ Duplaix 1980, p. 69
  69. ^ Noor, Dharna (25 May 2021). "Giant River Otter Believed to be Extinct Has Been Spotted in Argentina". Gizmodo. Retrieved 10 September 2023.
  70. ^ Duplaix 1980, pp. 523, 529
  71. ^ a b c Duplaix 1980, pp. 529–530
  72. ^ Lontra longicaudis. In Duplaix 1980 it was listed as the Guiana Otter under the older binomial Lutra enudris.
  73. ^ Duplaix 1980, pp. 527–9
  74. ^ Duplaix 1980, pp. 522, 529
  75. ^ . Convention on International Trade in Endangered Species of Wild Fauna and Flora. Archived from the original on 29 December 2007. Retrieved 22 January 2008.
  76. ^ a b c d Ridgley, Heidi (Winter 2007). "The Wolf of the River" (PDF). Defenders Magazine. Defenders of Wildlife. Retrieved 9 November 2007.
  77. ^ Zielinski, S. (1 May 2018). "How a social lifestyle helped drive a river otter species to near extinction". Science News. Retrieved 2 May 2018.
  78. ^ Slotow, R.; Pimenta, N. C.; Antunes, A. P.; Barnett, A. A.; Macedo, V. W.; Shepard, G. H. (30 March 2018). "Differential resilience of Amazonian otters along the Rio Negro in the aftermath of the 20th century international fur trade". PLOS ONE. 13 (3): e0193984. Bibcode:2018PLoSO..1393984P. doi:10.1371/journal.pone.0193984. PMC 5877832. PMID 29601590.
  79. ^ a b c d Wright, Lesley. "Threats to the Giant Otter". Otterjoy.com. Retrieved 25 January 2008.
  80. ^ Fonseca, Fabrizio R.D.; Malm, Olaf; Waldemarin, Helen F. (2005). "Mercury levels in tissues of Giant otters (Pteronura brasiliensis) from the Rio Negro, Pantanal, Brazil" (PDF). Environmental Research. 98 (3): 368–371. Bibcode:2005ER.....98..368D. doi:10.1016/j.envres.2004.11.008. PMID 15910792. Retrieved 9 November 2007.
  81. ^ Gutleb, A.C.; Schenck, C.; Staib, E. (December 1997). . Ambio. 26 (8): 511–514. Archived from the original on 27 November 2007. Retrieved 9 November 2007.
  82. ^ Schenck, Christof; Groenendijk, Jessica; Hajek, Frank (April 1999). "Giant Otter Project In Peru: Field Trip And Activity Report, 1998". IUCN Otter Specialist Group Bulletin. 16 (1): 33–43. Retrieved 22 January 2008.
  83. ^ Carter & Rosas 1998, p. 8
  84. ^ . Suriname Natcom. UNESCO. Archived from the original on 7 March 2007. Retrieved 21 January 2007.
  85. ^ a b Duplaix, Nicole; Lingaard, Marchal; Sakimin, Claudine (2001). "A Survey of Kaburi Creek, West Suriname, and its Conservation Implications" (PDF). The Oceanic Society. Retrieved 22 January 2008.
  86. ^ "Perú creará inmensa reserva amazónica" (in Spanish). BBC Mundo. 1 April 2005. Retrieved 7 January 2008.
  87. ^ . Round River Conservation Studies. Archived from the original on 10 January 2008. Retrieved 25 January 2008.
  88. ^ (Press release). The Ramsar Convention on Wetlands. 18 September 2001. Archived from the original on 22 February 2008. Retrieved 27 January 2008.
  89. ^ (in Spanish) Velasco, Diana Marcela (2005). "Estudio preliminar sobre el estado de conservación de la nutria gigante (Pteronura brasiliensis) en la zona de influencia de Inírida (Bajo río Inírida) Guainía, Colombia" (PDF). Giant Otter Research. Retrieved on 2008-01-27.
  90. ^ Lévi-Strauss, Claude (1983). The Raw and the Cooked. trans. John Weightman and Doreen Weightman. University of Chicago Press. pp. 104–108. ISBN 978-0-226-47487-8.
  91. ^ Landolt, Gredna (2005). El ojo que cuenta: Mitos y costumbres de la Amazonía indígena ilustrados. International Work Group for Indigenous Affairs. p. 81. ISBN 978-9972-2640-0-9.
  92. ^ Ching, César (October 2006). . BioDiversity Reporting Award. Semanario Kanatari, Iquitos, Iquitos (in Spanish). Archived from the original on 10 February 2012. Retrieved 27 January 2008.
  93. ^ Warren, Jonathan W. (26 September 2001). Racial Revolutions: Antiracism and Indian Resurgence in Brazil. Duke University Press. pp. 1–4. ISBN 978-0-8223-2741-7.

References

  • Carter, S.K.; Rosas, F.C.W. (1998). "Biology and conservation of Giant Otter (Pteronura brasiliensis)" (PDF). Mammal Review. 27 (1): 1–26. doi:10.1111/j.1365-2907.1997.tb00370.x. Retrieved 6 November 2007.
  • Duplaix, Nicole (1980). "Observations on the ecology and behavior of the giant river otter Pteronura brasiliensis in Suriname" (PDF). Revue d'Écologie (La Terre et la Vie). 34 (4): 495–620. doi:10.3406/revec.1980.4073. S2CID 140641854.

External links

 
Wikispecies has information related to Pteronura brasiliensis.
  •   Media related to Pteronura brasiliensis at Wikimedia Commons
  • ARKive –

April 26, 2024
giant, otter, giant, otter, giant, river, otter, pteronura, brasiliensis, south, american, carnivorous, mammal, longest, member, weasel, family, mustelidae, globally, successful, group, predators, reaching, atypical, mustelids, giant, otter, social, species, w. The giant otter or giant river otter 4 Pteronura brasiliensis is a South American carnivorous mammal It is the longest member of the weasel family Mustelidae a globally successful group of predators reaching up to 1 8 m 5 ft 11 in Atypical of mustelids the giant otter is a social species with family groups typically supporting three to eight members The groups are centered on a dominant breeding pair and are extremely cohesive and cooperative Although generally peaceful the species is territorial and aggression has been observed between groups The giant otter is diurnal being active exclusively during daylight hours It is the noisiest otter species and distinct vocalizations have been documented that indicate alarm aggression and reassurance Giant otter 1 Temporal range 0 13 0 Ma PreꞒ Ꞓ O S D C P T J K Pg N Late Pleistocene Holocene Cuiaba River Mato Grosso do Sul Brazil Conservation status Endangered IUCN 3 1 2 CITES Appendix I CITES 3 Scientific classification Domain Eukaryota Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Mustelidae Genus PteronuraGray 1837 Species P brasiliensis Binomial name Pteronura brasiliensis Gmelin 1788 Giant otter range The giant otter ranges across north central South America it lives mostly in and along the Amazon River and in the Pantanal Its distribution has been greatly reduced and is now discontinuous Decades of poaching for its velvety pelt peaking in the 1950s and 1960s considerably diminished population numbers The species was listed as endangered in 1999 and wild population estimates are typically below 5 000 The Guianas are one of the last real strongholds for the species which also enjoys modest numbers and significant protection in the Peruvian Amazonian basin It is one of the most endangered mammal species in the Neotropics Habitat degradation and loss is the greatest current threat They are also rare in captivity in 2003 only 60 giant otters were being held 5 The giant otter shows a variety of adaptations suitable to an amphibious lifestyle including exceptionally dense fur a wing like tail and webbed feet The species prefers freshwater rivers and streams which are usually seasonally flooded and may also take to freshwater lakes and springs It constructs extensive campsites close to feeding areas clearing large amounts of vegetation The giant otter subsists almost exclusively on a diet of fish particularly characins and catfish but may also eat crabs turtles snakes and small caimans 2 It has no serious natural predators other than humans although it must compete with other predators such as the Neotropical otters and various crocodilian species for food resources Contents 1 Name 2 Taxonomy and evolution 3 Physical characteristics 4 Biology and behaviour 4 1 Vocalizations 4 2 Social structure 4 3 Reproduction and life cycle 4 4 Hunting and diet 5 Ecology 5 1 Habitat 5 2 Predation and competition 6 Conservation status 6 1 Threats 6 2 Distribution and population 7 Interactions with indigenous peoples 8 Notes 9 References 10 External linksNameThe giant otter has a handful of other names In Brazil it is known as ariranha from the Tupi word ari rana meaning water jaguar Portuguese onca d agua 6 In Spanish river wolf Spanish lobo de rio and water dog Spanish perro de agua are used occasionally though the latter also refers to several different animals and may have been more common in the reports of explorers in the 19th and early 20th centuries 7 All four names are in use in South America with a number of regional variations Giant otter translates literally as nutria gigante and lontra gigante in Spanish and Portuguese respectively Among the Achuar people they are known as wankanim 8 among the Sanuma as hadami 9 10 verification needed and among the Makushi as turara 11 The genus name Pteronura is derived from the Ancient Greek words pteron pteron feather or wing and oὐra oura tail 12 a reference to its distinctive wing like tail 13 Taxonomy and evolution nbsp Giant otter head from the Museu Paraense Emilio Goeldi research institute The otters form the subfamily Lutrinae within the mustelids and the giant otter is the only member of the genus Pteronura Two subspecies are currently recognized by the canonical Mammal Species of the World P b brasiliensis and P b paraguensis Incorrect descriptions of the species have led to multiple synonyms the latter subspecies is often P b paranensis in the literature 1 P b brasiliensis is distributed across the north of the giant otter range including the Orinoco Amazon and Guianas river systems to the south P b paraguensis has been suggested in Paraguay Uruguay southern Brazil and northern Argentina 14 although it may be extinct in the last three of these four The International Union for Conservation of Nature IUCN considers the species presence in Argentina and Uruguay uncertain 2 In the former investigation has shown thinly distributed population remnants 15 P b paraguensis is supposedly smaller and more gregarious with different dentition and skull morphology Carter and Rosas however rejected the subspecific division in 1997 noting the classification had only been validated once in 1968 and the P b paraguensis type specimen was very similar to P b brasiliensis 16 Biologist Nicole Duplaix calls the division of doubtful value 17 The earliest fossil evidence of the giant river otter dates to the Late Pleistocene of Argentina and it was slightly larger than known modern specimens 18 An extinct genus Satherium is believed to be ancestral to the present species having migrated to the New World during the Pliocene or early Pleistocene 13 The giant otter shares the South American continent with three of the four members of the New World otter genus Lontra the Neotropical river otter the southern river otter and the marine otter 19 The North American river otter Lontra canadensis is the fourth Lontra member The giant otter seems to have evolved independently of Lontra in South America despite the overlap The smooth coated otter Lutrogale perspicillata of Asia may be its closest extant relative similar behaviour vocalizations and skull morphology have been noted 13 Both species also show strong pair bonding and paternal engagement in rearing cubs 20 Giant otter fossil remains have been recovered from a cave in the Brazilian Mato Grosso 21 Phylogenetic analysis by Koepfli and Wayne in 1998 found the giant otter has the highest divergence sequences within the otter subfamily forming a distinct clade that split away 10 to 14 million years ago They noted that the species may be the basal divergence among the otters or fall outside of them altogether having split even before other mustelids such as the ermine polecat and mink 13 Later gene sequencing research on the mustelids from 2004 places the divergence of the giant otter somewhat later between five and 11 million years ago the corresponding phylogenetic tree locates the Lontra divergence first among otter genera and Pteronura second although divergence ranges overlap 22 Physical characteristics nbsp A wild giant otter periscoping in Cantao State Park in Brazil showing its identifying throat marks nbsp Skull seen from the side Short snouted as usual in mustelids it has a pronounced sagittal crest allowing for a very powerful bite in this species The giant otter is clearly distinguished from other otters by morphological and behavioural characteristics It has the greatest body length of any species in the mustelid family although the sea otter may be heavier Males are between 1 5 and 1 7 m 4 ft 11 in and 5 ft 7 in in length from head to tail and females between 1 and 1 5 m 3 ft 3 1 2 in and 4 ft 11 in The animal s well muscled tail can add a further 70 cm 28 in to the total body length 23 24 Early reports of skins and living animals suggested exceptionally large males of up to 2 4 m 7 ft 10 1 2 in intensive hunting likely reduced the occurrence of such massive specimens Weights are between 26 and 32 kg 57 and 71 lb for males and 22 and 26 kg 49 and 57 lb for females 25 The giant otter has the shortest fur of all otter species it is typically chocolate brown but may be reddish or fawn and appears nearly black when wet 26 The fur is extremely dense so much so that water cannot penetrate to the skin 27 Guard hairs trap water and keep the inner fur dry the guard hairs are approximately 8 millimetres one third of an inch in length about twice as long as the fur of the inner coat 28 Its velvety feel makes the animal highly sought after by fur traders and has contributed to its decline 29 Unique markings of white or cream fur color the throat and under the chin allow individuals to be identified from birth 26 Giant otter muzzles are short and sloping and give the head a ball shaped appearance 17 The ears are small and rounded 27 The nose or rhinarium is completely covered in fur with only the two slit like nostrils visible The giant otter s highly sensitive whiskers vibrissae allow the animal to track changes in water pressure and currents which aids in detecting prey 30 The legs are short and stubby and end in large webbed feet tipped with sharp claws Well suited for an aquatic life it can close its ears and nose while underwater 31 At the time of Carter and Rosas s writing vision had not been directly studied but field observations show the animal primarily hunts by sight above water it is able to recognize observers at great distances The fact that it is exclusively active during the day further suggests its eyesight should be strong to aid in hunting and predator avoidance In other otter species vision is generally normal or slightly myopic both on land and in water The giant otter s hearing is acute and its sense of smell is excellent 26 32 The species possesses 2n 38 chromosomes 33 Biology and behaviourThe giant otter is large gregarious and diurnal Early travelers reports describe noisy groups surrounding explorers boats but little scientific information was available on the species until Duplaix s groundbreaking work in the late 1970s 34 Concern over this endangered species has since generated a body of research Vocalizations The giant otter is an especially noisy animal with a complex repertoire of vocalizations All otters produce vocalizations but by frequency and volume the giant otter may be the most vocal 35 Duplaix identified nine distinct sounds with further subdivisions possible depending on context Quick hah barks or explosive snorts suggest immediate interest and possible danger A wavering scream may be used in bluff charges against intruders while a low growl is used for aggressive warning Hums and coos are more reassuring within the group Whistles may be used as advance warning of nonhostile intent between groups although evidence is limited Newborn pups squeak to elicit attention while older young whine and wail when they begin to participate in group activities 36 An analysis published in 2014 cataloged 22 distinct types of vocalization in adults and 11 in neonates 37 Each family of otters was shown to have its own unique audio signature 38 Social structure The giant otter is a highly social animal and lives in extended family groups Group sizes are anywhere from two to 20 members but likely average between three and eight 14 Larger figures may reflect two or three family groups temporarily feeding together 39 nbsp Giant otters leave a pool together at the Philadelphia Zoo The species is extremely social a rarity among mustelids and family groups are cohesive Group members share roles structured around the dominant breeding pair The species is territorial with groups marking their ranges with latrines gland secretions and vocalizations 40 At least one case of a change in alpha relationship has been reported with a new male taking over the role the mechanics of the transition were not determined 41 Duplaix suggests a division between residents who are established within groups and territories and nomadic and solitary transients the categories do not seem rigid and both may be a normal part of the giant otter life cycle 42 One tentative theory for the development of sociality in mustelids is that locally abundant but unpredictably dispersed prey causes groups to form 43 Aggression within the species intraspecific conflict has been documented Defence against intruding animals appears to be cooperative while adult males typically lead in aggressive encounters cases of alpha females guarding groups have been reported 41 One fight was directly observed in the Brazilian Pantanal in which three animals violently engaged a single individual near a range boundary 40 In another instance in Brazil a carcass was found with clear indications of violent assault by other otters including bites to the snout and genitals an attack pattern similar to that exhibited by captive animals 44 While not rare among large predators in general intraspecific aggression is uncommon among otter species Ribas and Mourao suggest a correlation to the animal s sociability which is also rare among other otters 40 A capacity for aggressive behavior should not be overstated with the giant otter Researchers emphasize that even between groups conflict avoidance is generally adopted 45 46 Within groups the animals are extremely peaceful and cooperative Group hierarchies are not rigid and the animals easily share roles 47 Reproduction and life cycle nbsp A giant otter den dug on a lakeshore at Cantao State Park the newly dug white sand is a sign of recent activity at this den Giant otters build dens which are holes dug into riverbanks usually with multiple entrances and multiple chambers inside They give birth within these dens during the dry season In Cantao State Park otters dig their reproductive dens on the shores of oxbow lakes starting around July when waters are already quite low They give birth between August and September and the young pups emerge for the first time in October and November which are the months of lowest water when fish concentrations in the dwindling lakes and channels are at their peak This makes it easier for the adults to catch enough fish for the growing young and for the pups to learn how to catch fish The entire group including nonreproductive adults which are usually older siblings to that year s pups collaborates to catch enough fish for the young 48 Details of giant otter reproduction and life cycle are scarce and captive animals have provided much of the information Females appear to give birth year round although in the wild births may peak during the dry season The estrous cycle is 21 days with females receptive to sexual advances between three and 10 days 49 Study of captive specimens has found only males initiate copulation 5 At Tierpark Hagenbeck in Germany long term pair bonding and individualized mate selection were seen with copulation most frequently taking place in water 50 Females have a gestation period of 65 to 70 days giving birth to one to five pups with an average of two 49 50 Research over five years on a breeding pair at the Cali Zoo in Colombia found the average interval between litters was six to seven months but as short as 77 days when the previous litter did not survive 5 Other sources have found greater intervals with as long as 21 to 33 months suggested for otters in the wild 49 nbsp Captive giant otters have contributed greatly to scientific knowledge of the species by providing readily available subjects for research on the species reproduction and life cycle Mothers give birth to furred and blind cubs in an underground den near the river shore and fishing sites 51 Males actively participate in rearing cubs and family cohesion is strong 52 older juvenile siblings also participate in rearing although in the weeks immediately after birth they may temporarily leave the group 49 Pups open their eyes in their fourth week begin walking in their fifth and are able to swim confidently between 12 and 14 weeks old 5 They are weaned by nine months and begin hunting successfully soon after 49 The animal reaches sexual maturity at about two years of age and both male and female pups leave the group permanently after two to three years 49 50 They then search for new territory to begin a family of their own 53 Studies of giant otters in captivity have given indications about the environment necessary to both maintain a physically and behaviorally healthy population and allow successful cub rearing These include providing at least the minimum recommended land to water area ratio and that all enclosure land surfaces both artificial and natural are nearly entirely covered with the recommended substrate conditions e g tree bark mulch and soft pebble free sand soil Ensuring that the animals have sufficient privacy from human disturbances visual and acoustic from zoo staff or visitors at parturition and during cub rearing is also essential but not sufficient Insufficient land area proportions and unsuitable substrate conditions in zoos have historically been the primary cause of high cub mortality and physical and behavioral health problems among giant otters For example stress to the parents during cub rearing due to inappropriate enclosure conditions has been the primary reason for cub neglect abuse and infanticide 53 54 55 In the wild it has been suggested although not systematically confirmed that tourists cause similar stresses disrupted lactation and denning reduced hunting and habitat abandonment are all risks 53 This sensitivity is matched by a strong protectiveness towards the young All group members may aggressively charge intruders including boats with humans in them 56 The longest documented giant otter lifespan in the wild is eight years In captivity this may increase to 17 with an unconfirmed record of 19 The animal is susceptible to a variety of diseases including canine parvovirus Parasites such as the larvae of flies and a variety of intestinal worms also afflict the giant otter 53 Other causes of death include accidents gastroenteritis infanticide and epileptic seizures 49 Hunting and diet nbsp A captive giant otter when feeding grasps prey in its forepaws and begins eating immediately at the head The giant otter is an apex predator and its population status reflects the overall health of riverine ecosystems 57 It feeds mainly on fish including cichlids perch characins such as piranha and catfish 58 One full year study of giant otter scats in Amazonian Brazil found fish present in all fecal samples Fish from the order Perciformes particularly cichlids and perch were seen in 97 of scats and Characiformes such as characins in 86 Fish remains were of medium sized species that seem to prefer relatively shallow water to the advantage of the visually oriented giant otter Prey species found were also sedentary generally swimming only short distances which may aid the giant otter in predation 59 Hunting in shallow water has also been found to be more rewarding with water depth less than 0 6 metres 2 0 ft having the highest success rate 60 The giant otter seems to be opportunistic taking whatever species are most locally abundant 59 If fish are unavailable it will also take crabs snakes and even small caimans and anacondas 61 The species can hunt singly in pairs and in groups relying on sharp eyesight to locate prey 62 In some cases supposed cooperative hunting may be incidental a result of group members fishing individually in close proximity truly coordinated hunting may only occur where the prey cannot be taken by a single giant otter such as with small anacondas and juvenile black caiman 46 The giant otter seems to prefer prey fish that are generally immobile on river bottoms in clear water Prey chase is rapid and tumultuous with lunges and twists through the shallows and few missed targets The otter can attack from both above and below swiveling at the last instant to clamp the prey in its jaws Giant otters catch their own food and consume it immediately they grasp the fish firmly between the forepaws and begin eating noisily at the head 62 Carter and Rosas have found captive adult animals consume around 10 of their body weight daily about 3 kilograms 7 lb in keeping with findings in the wild 63 EcologyHabitatThe species is amphibious although primarily terrestrial 64 It occurs in freshwater rivers and streams which generally flood seasonally Other water habitats include freshwater springs and permanent freshwater lakes 2 Four specific vegetation types occur on one important creek in Suriname riverbank high forest floodable mixed marsh and high swamp forest floodable low marsh forest and grass islands and floating meadows within open areas of the creek itself 64 Duplaix identified two critical factors in habitat selection food abundance which appears to positively correlate to shallow water and low sloping banks with good cover and easy access to preferred water types The giant otter seems to choose clear black waters with rocky or sandy bottoms over silty saline and white waters 65 nbsp A group of four giant otters emerging from the water to patrol a campsite on the riverbank at Cantao State Park Giant otters use areas beside rivers for building dens campsites and latrines 66 They clear significant amounts of vegetation while building their campsites One report suggests maximum areas 28 m 92 ft long and 15 m 49 ft wide well marked by scent glands urine and feces to signal territory 19 Carter and Rosas found average areas a third this size Giant otters adopt communal latrines beside campsites and dig dens with a handful of entrances typically under root systems or fallen trees One report found between three and eight campsites clustered around feeding areas In seasonally flooded areas the giant otter may abandon campsites during the wet season dispersing to flooded forests in search of prey 67 Giant otters may adopt preferred locations perennially often on high ground These can become quite extensive including backdoor exits into forests and swamps away from the water 64 Otters do not visit or mark every site daily but usually patrol all of them often by a pair of otters in the morning 68 Research generally takes place in the dry season and an understanding of the species overall habitat use remains partial An analysis of dry season range size for three otter groups in Ecuador found areas between 0 45 and 2 79 square kilometres 0 17 and 1 08 sq mi Utreras 66 presumed habitat requirements and availability would differ dramatically in the rainy season estimating range sizes of 1 98 to as much as 19 55 square kilometres 0 76 to 7 55 sq miles for the groups Other researchers suggest approximately 7 square kilometres 2 7 sq mi and note a strong inverse correlation between sociality and home range size the highly social giant otter has smaller home range sizes than would be expected for a species of its mass 43 Population densities varied with a high of 1 2 km2 3 1 sq mi reported in Suriname and with a low of 0 154 km2 0 40 sq mi found in Guyana 14 In 2021 conservationists at Fundacion Rewilding spotted a wild giant otter swimming in the Bermejo River in Impenetrable National Park located in the Chaco province of northeast Argentina 69 Predation and competition nbsp Characins such as piranha species are prey for the giant otter but these aggressive fish may also pose a danger Duplaix speculated that piranhas may attack giant otters Adult giant otters living in family groups have no known serious natural predators however there are some accounts of black caimans in Peru and yacare caimans in the Pantanal preying on giant otters 63 In addition solitary animals and young may be vulnerable to attacks by the jaguar cougar and anaconda but this is based on historical reports not direct observation 70 Pups are more vulnerable and may be taken by caiman and other large predators 53 although adults are constantly mindful of stray young and will harass and fight off possible predators When in the water the giant otter faces danger from animals not strictly preying upon it the electric eel and stingray are potentially deadly if stumbled upon and piranha may be capable of at least taking bites out of a giant otter as evidenced by scarring on individuals 71 Even if without direct predation the giant otter must still compete with other predators for food resources Duplaix documented interaction with the Neotropical otter 72 While the two species are sympatric with overlapping ranges during certain seasons there appeared to be no serious conflict The smaller neotropical otter is far more shy less noisy and less social at about a third the weight of the giant otter it is more vulnerable to predation hence a lack of conspicuousness is to its advantage The neotropical otter is active during twilight and darkness reducing the likelihood of conflict with the diurnal giant otter 73 Its smaller prey different denning habits and different preferred water types also reduce interaction 63 Other species that prey upon similar food resources include the caimans and large fish that are themselves piscivores Gymnotids such as the electric eel and the large silurid catfish are among aquatic competitors Two river dolphins the tucuxi and Amazon river dolphin might potentially compete with the giant otter but different spatial use and dietary preferences suggest minimal overlap 63 Furthermore Defler observed associations between giant otters and the Amazon river dolphins and suggested that dolphins may benefit by fish fleeing from the otters 63 The spectacled caiman is another potential competitor but Duplaix found no conflict with the species in Suriname 74 Conservation statusThe IUCN listed the giant otter as endangered in 1999 it had been considered vulnerable under all previous listings from 1982 when sufficient data had first become available It is regulated internationally under Appendix I of the Convention on International Trade in Endangered Species of Wild Fauna and Flora CITES meaning commercial trade in specimens including parts and derivatives is prohibited 75 Threats The animal faces a variety of critical threats Poaching has long been a problem Statistics show between 1959 and 1969 Amazonian Brazil alone accounted for 1 000 to 3 000 pelts annually The species was so thoroughly decimated the number dropped to just 12 in 1971 The implementation of CITES in 1973 finally brought about significant hunting reductions 14 although demand did not disappear entirely in the 1980s pelt prices were as high as US 250 on the European market The threat has been exacerbated by the otters relative fearlessness and tendency to approach human beings They are extremely easy to hunt being active through the day and highly inquisitive 76 The animal s relatively late sexual maturity and complex social life makes hunting especially disastrous 14 77 78 More recently habitat destruction and degradation have become the principal dangers and a further reduction of 50 is expected in giant otter numbers within the 25 years after 2020 about the span of three generations of giant otters 2 Typically loggers first move into rainforest clearing the vegetation along riverbanks Farmers follow creating depleted soil and disrupted habitats As human activity expands giant otter home ranges become increasingly isolated Subadults leaving in search of new territory find it impossible to set up family groups 79 Specific threats from human industry include unsustainable mahogany logging in parts of the giant otter range 76 and concentrations of mercury in its diet of fish a byproduct of gold mining 80 81 Other threats to the giant otter include conflict with fishermen who often view the species as a nuisance see below Ecotourism also presents challenges while it raises money and awareness for the animals by its nature it also increases human effect on the species both through associated development and direct disturbances in the field 79 A number of restrictions on land use and human intrusion are required to properly maintain wild populations Schenck et al who undertook extensive fieldwork in Peru in the 1990s suggest specific no go zones where the species is most frequently observed offset by observation towers and platforms to allow viewing Limits on the number of tourists at any one time fishing prohibitions and a minimum safe distance of 50 metres 164 ft are proposed to offer further protection 82 Distribution and population nbsp Giant otter from VenezuelaThe giant otter has lost as much as 80 of its South American range 76 While still present in a number of north central countries giant otter populations are under considerable stress The IUCN lists Bolivia Brazil Colombia Ecuador French Guiana Guyana Paraguay Peru Suriname and Venezuela as current range countries 2 Given local extinctions the species range has become discontinuous 14 Total population numbers are difficult to estimate 2 Populations in Bolivia were once widespread but the country became a black spot on distribution maps after poaching between the 1940s and 1970s a relatively healthy but still small population of 350 was estimated in the country in 2002 39 The species has likely been extirpated from southern Brazil but in the west of the country decreased hunting pressure in the critical Pantanal has led to very successful recolonization an estimate suggests 1 000 or more animals in the region 76 83 nbsp The Guianas are the last real stronghold of the giant otter Suriname retains extensive forest cover and many protected areas it is pictured above Guyana is immediately to the west and French Guiana is immediately to the east As of 2020 the IUCN estimates that there may be 4 569 otters living in Brazil 2 A significant population lives in the wetlands of the central Araguaia River and in particular within Cantao State Park which with its 843 oxbow lakes and extensive flooded forests and marshlands is one of the best habitat patches for this species in Brazil 48 Suriname still has significant forest cover and an extensive system of protected areas much of which protects the giant otter 84 Duplaix returned to the country in 2000 and found the giant otter still present on the Kaburi Creek a jewel of biodiversity although increased human presence and land use suggests sooner or later the species may not be able to find suitable habitat for campsites 85 In a report for World Wildlife Fund in 2002 Duplaix was emphatic about the importance of Suriname and the other Guianas 64 The three Guianas remain the last stronghold of giant otters in South America with pristine giant otter habitat on some rivers and good giant otter densities overall still but for how long The survival of the giant otter populations in the Guianas is essential to the survival of this endangered species in South America Other countries have taken a lead in designating protected areas in South America In 2004 Peru created one of the largest conservation areas in the world Alto Purus National Park with an area similar in size to Belgium The park harbors many endangered plants and animals including the giant otter and holds the world record for mammal diversity 86 87 Bolivia designated wetlands larger than the size of Switzerland as a freshwater protected area in 2001 these are also home to the giant otter 88 Interactions with indigenous peoplesThroughout its range the giant otter interacts with indigenous groups who often practice traditional hunting and fishing A study of five indigenous communities in Colombia suggests native attitudes toward the animal are a threat the otters are often viewed as a nuisance that interferes with fishing and are sometimes killed Even when told of the importance of the species to ecosystems and the danger of extinction interviewees showed little interest in continuing to coexist with the species Schoolchildren however had a more positive impression of the animal 89 In Suriname the giant otter is not a traditional prey species for human hunters which affords some protection 85 One researcher has suggested the giant otter is hunted only in desperation due to its horrible taste 79 The animal sometimes drowns in nets set across rivers and machete attacks by fishermen have been noted according to Duplaix but tolerance is the rule in Suriname 71 One difference in behavior was seen in the country in 2002 the normally inquisitive giant otters showed active avoidance behavior with visible panic when boats appeared Logging hunting and pup seizure may have led groups to be far more wary of human activity 64 Local people sometimes take pups for the exotic pet trade or as pets for themselves but the animal rapidly grows to become unmanageable 79 Duplaix relates the story of an Arawak Indian who took two pups from their parents While revealing of the affection held for the animals the seizure was a profound blow to the breeding pair which went on to lose their territory to competitors 71 The species has also appeared in the folklore of the region It plays an important role in the mythology of the Achuar people where giant otters are seen as a form of the tsunki or water spirits they are a sort of water people who feed on fish They appear in a fish poisoning legend where they assist a man who has wasted his sexual energy creating the anacondas of the world from his distressed and extended genitals 8 The Bororo people have a legend on the origin of tobacco smoking those who used the leaf improperly by swallowing it were punished by being transformed into giant otters the Bororo also associate the giant otter with fish and with fire 90 A Ticuna legend has it that the giant otter exchanged places with the jaguar the story says jaguar formerly lived in the water and the giant otter came to the land only to eat 91 The indigenous Kichwa peoples from Amazonian Peru believed in a world of water where Yaku runa reigned as mother of the water and was charged with caring for fish and animals Giant otters served as Yaku runa s canoes 92 A Maxacali creation story suggests that the practice of otter fishing may have been prevalent in the past 93 Notes a b Wozencraft W C 2005 Order Carnivora In Wilson D E Reeder D M eds Mammal Species of the World A Taxonomic and Geographic Reference 3rd ed Johns Hopkins University Press p 605 ISBN 978 0 8018 8221 0 OCLC 62265494 a b c d e f g h Groenendijk J Leuchtenberger C Marmontel M Van Damme P Wallace R Schenck C 2022 amended version of 2021 assessment Pteronura brasiliensis IUCN Red List of Threatened Species 2022 e T18711A222719180 doi 10 2305 IUCN UK 2022 2 RLTS T18711A222719180 en Retrieved 10 September 2023 Appendices CITES cites org Retrieved 14 January 2022 Giant river otter National Geographic Society 10 March 2011 Archived from the original on 12 January 2010 Retrieved 6 August 2016 a b c d Londono G Corredor Munoz N Tigreros 2006 Reproduction behaviour and biology of the Giant river otter Pteronura brasiliensis at Cali Zoo International Zoo Yearbook 40 360 371 doi 10 1111 j 1748 1090 2006 00360 x Ferreira A B H 1986 Novo Dicionario da Lingua Portuguesa 2nd ed Nova Fronteira p 163 See e g Duplaix 1980 p 547 a b Descola Philippe 1994 In the Society of Nature A Native Ecology in Amazonia Cambridge University Press pp 280 282 ISBN 978 0 521 41103 5 Ramos Alcida Rita 1995 Sanuma Memories Yanomami Ethnography in Times of Crisis University of Wisconsin Press p 219 ISBN 978 0 299 14654 2 none Antropologica 1981 1982 volume 55 58 page 107 Mammals of Iwokrama iwokrama org Retrieved 6 February 2023 Liddell Henry George amp Robert Scott 1980 A Greek English Lexicon Abridged ed United Kingdom Oxford University Press ISBN 978 0 19 910207 5 a b c d Koepfli K P Wayne R K December 1998 Phylogenetic relationships of otters Carnivora Mustelidae based on mitochondrial cytochrome b sequences Journal of Zoology 246 4 401 416 doi 10 1111 j 1469 7998 1998 tb00172 x a b c d e f Pteronura brasiliensis giant otter Carnivores Food and agricultural organization of the United Nations Archived from the original on 27 November 2007 Retrieved 7 November 2007 Chehebar C February 1991 Searching for the Giant Otter in Northeastern Argentina IUCN Otter Specialist Group Bulletin 6 1 17 18 Retrieved 6 November 2007 Carter amp Rosas 1998 p 4 a b Duplaix 1980 p 511 Prevosti Francisco J Ferrero Brenda S 2008 A Pleistocene giant river otter from Argentina remarks on the fossil record and phylogenetic analysis Journal of Vertebrate Paleontology 28 4 1171 1181 Bibcode 2008JVPal 28 1171P doi 10 1671 0272 4634 28 4 1171 hdl 11336 80190 a b Foster Turley Pat Macdonald Sheila Mason Chris eds 1990 Otters An Action Plan for their Conservation IUCN SSC Otter Specialist Group Sections 2 and 12 Archived from the original on 5 January 2008 Retrieved 21 November 2007 Duplaix 1980 p 614 Cartelle Castor Hirooka Suzana September 2005 Primeiro Registro Pleistocenico de Pteronura brasiliensis Gmelin 1788 Carnivora Mustelidae Research Gate Arquivos do Museu Nacional Rio de Janeiro Publishing Retrieved 9 October 2018 Marmi Josep Lopez Giraldez Juan F Domingo Roura Xavier November 2004 Phylogeny evolutionary history and taxonomy of the Mustelidae based on sequences of the cytochrome b gene and a complex repetitive flanking region Zoologica Scripta 33 6 481 499 doi 10 1111 j 0300 3256 2004 00165 x S2CID 85818256 Giant Otter Pteronura brasiliensis The Nature Conservancy Archived from the original on 25 May 2009 Retrieved 25 January 2008 Boitani Luigi Simon amp Schuster s Guide to Mammals Simon amp Schuster Touchstone Books 1984 ISBN 978 0 671 42805 1 Duplaix 1980 a b c Carter amp Rosas 1998 p 2 a b Giant Otter Meet Our Animals Philadelphia Zoo Archived from the original on 11 April 2013 Retrieved 6 November 2007 Otters Physical characteristics Anheuser Busch Adventure Parks Archived from the original on 2 November 2007 Retrieved 6 November 2007 Giant Otter Facts Meet Our Animals Earth s Endangered Creatures Retrieved 7 November 2007 Giant Otter World Wildlife Fund Archived from the original on 24 October 2007 Retrieved 19 January 2008 Giant Otter the Water Dog Iwokrama International Centre for Rainforest Conservation and Development Archived from the original on 17 October 2007 Retrieved 7 November 2007 Duplaix 1980 p 533 Franco de Sa J F O Rosas F C W Feldberg E 2007 Cytogenetic study of the giant otter Pteronura brasiliensis Zimmermann 1780 Carnivora Mustelidae Lutrinae Genetics and Molecular Biology 30 4 1093 1096 doi 10 1590 S1415 47572007000600011 Duplaix 1980 p 497 Otters A SeaWorld Education Department Publication PDF Seaworld 2005 Archived from the original PDF on 15 July 2008 Retrieved 23 January 2008 Duplaix 1980 pp 552 561 Mumm C A S Knornschild M 12 November 2014 The Vocal Repertoire of Adult and Neonate Giant Otters Pteronura brasiliensis PLOS ONE 9 11 e112562 Bibcode 2014PLoSO 9k2562M doi 10 1371 journal pone 0112562 PMC 4229255 PMID 25391142 Mumm C A Knornschild M 2017 Territorial choruses of giant otter groups Pteronura brasiliensis encode information on group identity PLOS ONE 12 10 e0185733 Bibcode 2017PLoSO 1285733M doi 10 1371 journal pone 0185733 PMC 5638252 PMID 29023545 a b van Damme Paul Wallace Rob Swaenepoel Karen Painter Lillian Ten Silvia Taber Andrew et al October 2002 Distribution and Population Status of the Giant Otter Pteronura brasiliensis in Bolivia IUCN Otter Specialist Group Bulletin 19 2 87 96 Retrieved 5 November 2007 a b c Ribas Carolina Mourao Guilherme January 2005 Intraspecific Agonism between Giant Otter Groups IUCN Otter Specialist Group Bulletin 21 2 89 93 Retrieved 7 November 2007 a b Evangelista Emanuela July 2004 Change of Partners in a Giant Otter Alpha Couple IUCN Otter Specialist Group Bulletin 21 1 47 51 Retrieved 7 November 2007 Duplaix 1980 pp 571 2 a b Johnson Dominic D P MacDonald David W Dickman Amy J 2000 An analysis and review of the sociobiology of the Mustelidae PDF Mammal Review 30 3 amp 4 171 196 doi 10 1046 j 1365 2907 2000 00066 x Archived from the original PDF on 19 September 2006 Retrieved 7 November 2007 See figure three for home range size estimate Rosas F C W De Mattos G E October 2003 Natural Deaths of Giant Otters Pteronura brasiliensis In Balbina Hydroelectric Lake Amazonas Brazil IUCN Otter Specialist Group Bulletin 20 2 62 64 Retrieved 7 November 2007 Duplaix 1980 p 563 a b Carter amp Rosas 1998 p 15 Schenck C Staib E April 1992 Giant Otters in Peru IUCN Otter Specialist Group Bulletin 7 24 26 Retrieved 22 January 2008 a b Giant Otters in Cantao Instituto Araguaia Archived from the original on 26 June 2017 Retrieved 10 March 2011 a b c d e f g Carter amp Rosas 1998 p 18 a b c Hagenbeck Carl Wunnemann Claus 1992 Breeding the giant otter Pteronura brasiliensis at Carl Hagenbecks Tierpark International Zoo Yearbook 32 240 245 doi 10 1111 j 1748 1090 1991 tb02392 x Duplaix 1980 p 567 Duplaix 1980 p 576 a b c d e Sykes Gatz S 2005 International Giant Otter Studbook Husbandry and Management Information and Guidelines Second ed Germany Zoologischer Garten Dortmund p 13 Sykes Gatz S Gatz V 2011 International Studbook for the Giant Otter Pteronura brasiliensis Gray 1867 2nd ed Germany Zoologischer Garten Dortmund Gatz V Sykes Gatz S Giant Otter EEP Annual Report 2003 2007 2010 Report EAZA Yearbook 2003 2007 2010 Amsterdam EAZA Executive Office European Association of Zoos and Aquariums Duplaix 1980 pp 564 5 570 Barnett Adrian Shapley Rebecca Lehman Shawn Henry Everton Benjamin Paul October 2000 Records of the Giant Otter Pteronura brasiliensis from Guyana PDF IUCN Otter Specialist Group Bulletin 17 2 65 74 Retrieved 10 September 2023 via rebeccashapley com Bender Jamie Pteronura brasiliensis giant otter Animal Diversity Web a b Rosas Fernando C W Zuanon Jansen A S Carter Sarah K September 1999 Feeding Ecology of the Giant Otter Pteronura brasiliensis Biotropica 31 3 502 506 Bibcode 1999Biotr 31 502R doi 10 1111 j 1744 7429 1999 tb00393 x S2CID 86658847 Carter amp Rosas 1998 p 16 Giant Otter Pteronura brasiliensis International Otter Survival Fund Archived from the original on 11 October 2007 Retrieved 21 November 2007 a b Duplaix 1980 pp 544 6 a b c d e Carter amp Rosas 1998 p 17 a b c d e Duplaix Nicole 2002 Guianas Rapid River Bio assessments and Giant Otter Conservation Project PDF Report World Wildlife Fund Duplaix 1980 pp 514 5 a b Utreras B V Suarez R E Zapata Rios G Lasso G Pinos L July December 2005 Dry and Rainy Season Estimations of Giant Otter Pteronura brasiliensis Home Range in the Yasuni National Park Ecuador PDF The Latin American Journal of Aquatic Mammals 4 2 191 194 doi 10 5597 lajam00085 Retrieved 7 November 2007 Carter amp Rosas 1998 p 13 Duplaix 1980 p 69 Noor Dharna 25 May 2021 Giant River Otter Believed to be Extinct Has Been Spotted in Argentina Gizmodo Retrieved 10 September 2023 Duplaix 1980 pp 523 529 a b c Duplaix 1980 pp 529 530 Lontra longicaudis In Duplaix 1980 it was listed as the Guiana Otter under the older binomial Lutra enudris Duplaix 1980 pp 527 9 Duplaix 1980 pp 522 529 Appendices I II and III Convention on International Trade in Endangered Species of Wild Fauna and Flora Archived from the original on 29 December 2007 Retrieved 22 January 2008 a b c d Ridgley Heidi Winter 2007 The Wolf of the River PDF Defenders Magazine Defenders of Wildlife Retrieved 9 November 2007 Zielinski S 1 May 2018 How a social lifestyle helped drive a river otter species to near extinction Science News Retrieved 2 May 2018 Slotow R Pimenta N C Antunes A P Barnett A A Macedo V W Shepard G H 30 March 2018 Differential resilience of Amazonian otters along the Rio Negro in the aftermath of the 20th century international fur trade PLOS ONE 13 3 e0193984 Bibcode 2018PLoSO 1393984P doi 10 1371 journal pone 0193984 PMC 5877832 PMID 29601590 a b c d Wright Lesley Threats to the Giant Otter Otterjoy com Retrieved 25 January 2008 Fonseca Fabrizio R D Malm Olaf Waldemarin Helen F 2005 Mercury levels in tissues of Giant otters Pteronura brasiliensis from the Rio Negro Pantanal Brazil PDF Environmental Research 98 3 368 371 Bibcode 2005ER 98 368D doi 10 1016 j envres 2004 11 008 PMID 15910792 Retrieved 9 November 2007 Gutleb A C Schenck C Staib E December 1997 Giant otter Pteronura brasiliensis at risk Total mercury and methylmercury levels in fish and otter scats Peru Ambio 26 8 511 514 Archived from the original on 27 November 2007 Retrieved 9 November 2007 Schenck Christof Groenendijk Jessica Hajek Frank April 1999 Giant Otter Project In Peru Field Trip And Activity Report 1998 IUCN Otter Specialist Group Bulletin 16 1 33 43 Retrieved 22 January 2008 Carter amp Rosas 1998 p 8 Natural Heritage in Suriname Suriname Natcom UNESCO Archived from the original on 7 March 2007 Retrieved 21 January 2007 a b Duplaix Nicole Lingaard Marchal Sakimin Claudine 2001 A Survey of Kaburi Creek West Suriname and its Conservation Implications PDF The Oceanic Society Retrieved 22 January 2008 Peru creara inmensa reserva amazonica in Spanish BBC Mundo 1 April 2005 Retrieved 7 January 2008 The Alto Purus Conservation Project Round River Conservation Studies Archived from the original on 10 January 2008 Retrieved 25 January 2008 WWF welcomes Latin America s largest freshwater protected area Press release The Ramsar Convention on Wetlands 18 September 2001 Archived from the original on 22 February 2008 Retrieved 27 January 2008 in Spanish Velasco Diana Marcela 2005 Estudio preliminar sobre el estado de conservacion de la nutria gigante Pteronura brasiliensis en la zona de influencia de Inirida Bajo rio Inirida Guainia Colombia PDF Giant Otter Research Retrieved on 2008 01 27 Levi Strauss Claude 1983 The Raw and the Cooked trans John Weightman and Doreen Weightman University of Chicago Press pp 104 108 ISBN 978 0 226 47487 8 Landolt Gredna 2005 El ojo que cuenta Mitos y costumbres de la Amazonia indigena ilustrados International Work Group for Indigenous Affairs p 81 ISBN 978 9972 2640 0 9 Ching Cesar October 2006 PER I38 El mundo del agua temido y poco conocido BioDiversity Reporting Award Semanario Kanatari Iquitos Iquitos in Spanish Archived from the original on 10 February 2012 Retrieved 27 January 2008 Warren Jonathan W 26 September 2001 Racial Revolutions Antiracism and Indian Resurgence in Brazil Duke University Press pp 1 4 ISBN 978 0 8223 2741 7 ReferencesCarter S K Rosas F C W 1998 Biology and conservation of Giant Otter Pteronura brasiliensis PDF Mammal Review 27 1 1 26 doi 10 1111 j 1365 2907 1997 tb00370 x Retrieved 6 November 2007 Duplaix Nicole 1980 Observations on the ecology and behavior of the giant river otter Pteronura brasiliensis in Suriname PDF Revue d Ecologie La Terre et la Vie 34 4 495 620 doi 10 3406 revec 1980 4073 S2CID 140641854 External links nbsp Wikispecies has information related to Pteronura brasiliensis nbsp Media related to Pteronura brasiliensis at Wikimedia Commons ARKive images and movies of the giant otter Pteronura brasiliensis Portal nbsp Animals Retrieved from https en wikipedia org w index php title Giant otter amp oldid 1220576629, wikipedia, wiki, book, books, library,

article

, read, download, free, free download, mp3, video, mp4, 3gp, jpg, jpeg, gif, png, picture, music, song, movie, book, game, games.