Free Teacher Resources
Two giant otters resting together on a log.
Photo: Charles J. Sharp, CC BY-SA 4.0, via Wikimedia Commons

Giant Otter

Pteronura brasiliensis

The longest otter in the world, a fish-hunting "river wolf" of the Amazon that lives and hunts in family groups.

🦦 Weasels and Otters
Checking teacher reviews…
Teacher? Sign in to review this page →Report a mistake

About the Giant Otter

Giant otters live in rivers, streams and wetlands across almost the whole Amazon Basin and north into countries like Suriname and Guyana. Males are 5 to 6 feet long. Thick fur keeps their skin dry while they swim, and long whiskers help them feel for prey in murky water. They eat mostly fish, plus prawns, frogs, small caimans and snakes.[1]

Quick facts

Scientific name
Pteronura brasiliensis[1]
Size
Males 5 to 6 feet long. Tail can be longer than 27 inches.[1]
Weight
Males 55 to 70 pounds. Females are slightly smaller.[1]
Lifespan
About 10 to 12 years on average.[1]
Diet
Carnivore. Mostly fish, plus prawns, frogs, small caimans and snakes.[1]
Habitat
Rivers, streams and wetlands.[1]
Where it lives
The Amazon Basin and the Guiana Shield, in countries such as Suriname and Guyana.[1]
Group life
Family groups of up to 10. Active during the day.[1]
Babies
Pregnancy lasts 65 to 70 days. One to five pups, usually two.[1]
Conservation status
Endangered (IUCN Red List, assessed 2020).[2]

Fun facts

  • Giant otters are called "river wolves" in South America.[1]
  • The pale patches on each otter's throat form a pattern unique to that otter.[1]
  • Young giant otters have to be taught to swim by their parents.[1]
  • Giant otters can make up to 15 different kinds of calls.[1]

Vocabulary

mustelid
A member of the weasel family, which includes otters, mink and badgers.
predator
An animal that hunts other animals for food.
whiskers
Long, stiff hairs on an animal's face that sense touch and movement.
murky
Dark and cloudy, hard to see through.
endangered
A conservation label meaning a species faces a very high risk of dying out in the wild.

See it in person

Sources

  1. [1] Zoo Atlanta. “Giant Otter.” https://zooatlanta.org/animal/giant-otter/ (accessed 2026-10-02)
  2. [2] IUCN Red List of Threatened Species. “Pteronura brasiliensis (Giant Otter).” https://www.iucnredlist.org/species/18711/222719180 (accessed 2026-10-02)

Facts last checked 2026-10-02.