Perfectly adapted to an amphibious lifestyle, the giant otter (Pteronura brasiliensis) is the longest member of the Mustelidae (weasel) family, reaching nearly 6 feet from head to tail. Once widespread across South America, the giant otter’s distribution is becoming increasingly fragmented and they are therefore endangered.
Found around freshwater rivers and streams, like the Amazon river, the giant otter’s diet mainly consists of fish. However, they also feed on crabs, turtles, snakes and even small caimans and anacondas! Their food intake is intense; individuals must consume around 3kg of food every day. Due to their semi-aquatic lifestyle, the giant otter has evolved a plethora of adaptations to better their survival. Namely, they have powerful tails to propel themselves through the water and webbed feet that act like flippers. Moreover, giant otters have exceptionally dense, water-repellent fur to keep them dry and warm. When underwater, they are able to close their ears and nostrils.
Rather unusually for mustelids, giant otters are highly social animals, living in medium-sized groups (anywhere from 2 to 20 individuals) centred around a dominant breeding pair. These groups are tight-knit and territorial; they sleep, hunt, travel and play together. Giant otters live in dens – holes dug into riverbanks – which is where they give birth to 1-5 pups per pregnancy.
An apex predator, the giant otter is vitally important to the health and stability of aquatic ecosystems in South America. With its varied diet, including species that most other animals would be unable to tackle, this mammal helps to control the populations of the continent’s species. Unfortunately, the giant otter is under threat. Poaching, habitat destruction, pollution, the increasing use of pesticides, conflict with fishermen and other human disturbances endanger the survival of this otter. Estimates suggest their population numbers fewer than 5,000 individuals. Conservation strategies such as encouraging fishermen to use nets that won’t trap the otters are being implemented but much more must be done to ensure their survival.