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Giant otter

The giant otter (*Pteronura brasiliensis*) is the largest otter species and the only living species in the genus *Pteronura*.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

The giant otter (*Pteronura brasiliensis*) is the largest otter species and the only living species in the genus *Pteronura*. It is a semiaquatic carnivorous mammal native to South America, where it lives in freshwater habitats across parts of the Amazon, Orinoco, and La Plata river systems. The species is listed as Endangered by the IUCN.

Taxonomy and naming

The giant otter is scientifically known as *Pteronura brasiliensis* and belongs to the weasel family, Mustelidae. It is the sole living species in its genus, *Pteronura*.

Description

The giant otter is the largest otter species, with adult lengths commonly reported up to about 1.8 m. It has a long body, webbed feet, and a tail adapted for swimming.

Distribution and habitat

The species occurs in freshwater ecosystems in South America, especially within the Amazon, Orinoco, and La Plata river systems. It prefers rivers, creeks, lakes, and swamps with slow-moving water.

Behaviour and diet

Giant otters are social animals that live in family groups and are active hunters in aquatic habitats. Their diet consists mainly of fish.

Conservation

The giant otter is listed as Endangered by the IUCN. Population declines have been linked to habitat destruction, pollution, and poaching.

Key facts

  • It is the largest otter species and can reach about 1.8 m in length.
  • The giant otter is native to South America.
  • It is the only extant species in the genus Pteronura.
  • Main threats include habitat loss, pollution, and poaching.
  • It is classified as Endangered by the IUCN.
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Canadian context

Giant otters are not native to Canada, but they are relevant to Canadian zoo collections, wildlife education, and conservation discussions about endangered South American mammals.

Frequently asked questions

What is the scientific name of the giant otter?
The scientific name is *Pteronura brasiliensis*.
Where do giant otters live?
They live in freshwater habitats in South America, especially in the Amazon, Orinoco, and La Plata river systems.
How big is a giant otter?
It is the largest otter species and can grow to about 1.8 m long.
What do giant otters eat?
They eat mainly fish.
Is the giant otter endangered?
Yes. The IUCN lists the species as Endangered.
Is the giant otter the only species in its genus?
Yes. It is the only living species in the genus *Pteronura*.

References

  1. National Geographichttps://www.nationalgeographic.com/animals/mammals/facts/giant-otter
    Supports: Scientific name, largest otter species, South American range, endangered status
  2. Discover Wildlifehttps://www.discoverwildlife.com/animal-facts/mammals/facts-about-giant-otters
    Supports: Largest otter species, genus, habitat, reproduction, endangered status
  3. Otter Specialist Grouphttps://www.otter.org/giant-otter
    Supports: Species identity, conservation status, social behaviour
  4. WorldAtlashttps://www.worldatlas.com/articles/giant-otter-facts-animals-of-south-america.html
    Supports: Family groups, distribution, conservation threats