Interesting Animals


Conservation Status:
Endangered


Regions:
South America


Habitats:
River


Diet:
Carnivore


Family:
Mustelidae (Weasels)

Giant Otter

IUCN Red List Conservation Status


Endangered

LC
NT
VU
EN
CR
EW
EX

Official assessment evaluated in accordance with the IUCN Red List of Threatened Species criteria: Endangered.


Species Quick Facts

Scientific Name
Pteronura brasiliensis

Average Lifespan
10-12 years in the wild, up to 21 years in captivity

Average Weight
Males 26-32 kg (57-70 lbs); females 22-26 kg (48-57 lbs)

Average Length
1-1.7 m (3.3-5.6 feet) head-body length; muscular tail adds up to 70 cm (28 inches)

Overview & Identification

The giant otter is the largest member of the weasel family, a social, river-dwelling carnivore of the Amazon, Orinoco, and Pantanal regions of South America. Reaching up to 1.8 m long, it has dense brown fur, webbed feet, and a flattened tail, and lives in noisy family groups that hunt fish cooperatively. Endangered by habitat destruction and past hunting for its pelt, it is sometimes called the river wolf.

Behavior & Social Structure

Highly social for an otter, living in extended family groups of roughly four to eight individuals that hunt, groom, rest, and communicate together using at least nine distinct vocalizations, while still defending a family territory.

Diet & Hunting Patterns

Feeds mainly on fish, especially catfish, characins, and perch-like species, hunted by sight along river and lake margins; will also take crustaceans, small caimans, and snakes when fish are scarce.

Reproduction & Life Cycle

Breeds seasonally, with pups typically born between August and October after a gestation of 65-70 days; litters usually contain one to five pups, and older siblings help raise the young.

Threats & Conservation

Listed as Endangered, with populations having declined by more than half in the past 15 years; primary threats are habitat destruction, water pollution and mercury contamination from gold mining, and historical hunting for its pelt.

Interesting Facts

• Species Profile

• brown, is designed to provide insulation in the water. Notably, the Giant Otter’s throat is white, serving as a distinctive feature that sets it apart from other otter species.

• floodable banks, abundant vegetation cover, and high fish densities. They prefer habitats with clean water and minimal human disturbance, as these conditions are essential for their survival and well-being. The species is known to create dens in riverbank burrows, utilizing thick vegetation for shelter and breeding.

• water wetlands of South America.

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Giant Otter (Pteronura brasiliensis) – Species Profile

Description

The Giant Otter, scientifically known as Pteronura brasiliensis, is a remarkable South American carnivorous mammal. It holds the title of being the longest member of the weasel family, Mustelidae, which is a globally successful group of predators. Known for its sociable nature and distinct vocalizations, the Giant Otter is a fascinating and integral part of the South American aquatic ecosystems.

Appearance

The Giant Otter is renowned for its striking appearance, characterized by a sleek, elongated body, webbed feet, and a flattened tail that aids in efficient swimming. Its lustrous fur, which ranges from dark brown to reddish-brown, is designed to provide insulation in the water. Notably, the Giant Otter’s throat is white, serving as a distinctive feature that sets it apart from other otter species.

Distribution

The Giant Otter is primarily found in the freshwater habitats of South America, including the Amazon, Orinoco, and La Plata river systems. Its range extends across countries such as Brazil, Peru, Colombia, Venezuela, and Bolivia. However, due to habitat loss and human encroachment, the species faces localized population declines in certain regions.

Habitat Preferences

Giant Otters thrive in pristine freshwater ecosystems with non-floodable banks, abundant vegetation cover, and high fish densities. They prefer habitats with clean water and minimal human disturbance, as these conditions are essential for their survival and well-being. The species is known to create dens in riverbank burrows, utilizing thick vegetation for shelter and breeding.

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Facts About Giant Otter
1. The giant otter (Pteronura brasiliensis) is the largest otter species, growing up to 1.8 meters in length.
2. Giant otters are native to the fresh-water wetlands of South America.
3. They are social animals, living in family groups of up to 20 individuals.
4. Giant otters are top predators in their habitat, mainly preying on fish.
5. Their vocalizations include a complex repertoire of sounds for communication within the group.
6. Giant otters are well adapted for an aquatic lifestyle, with webbed feet and strong, streamlined bodies.
7. The species is listed as endangered on the IUCN Red List due to habitat loss and poaching.
8. Their diet primarily consists of fish, but they may also consume crustaceans and small mammals.
9. Giant otters construct extensive dens with multiple chambers along riverbanks.
10. They play a crucial role in maintaining the health of riverine ecosystems through their predatory and foraging activities.


Scientific Provenance & Verified Sources

Biological taxonomy, conservation status, and physical traits are cross-referenced with authoritative global registers:



Peer-reviewed by Wildlife Science Editors • Updated for 2026

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