Habitat – Rivers
Niche – Large Opportunistic Predator
Favorite Food – Fish and Crustaceans
Length – between 4 and 6 feet, nose to tail tip
Weight – up to 70 pounds
Status – Endangered
Threats – Habitat loss, pollution, hunting
Giant otters are the largest members of the mustelid family, a group of mammals that also includes weasels, badgers, and skunks. Otters are the only mustelids to carve out a true niche in the water, and the giant otter is perfectly adapted to life in the extensive river system of South America.
Like all otters, the giant otter has evolved for hunting in the water. It has a streamlined, torpedo-shaped body with a long flattened tail and webbed feet for propulsion through the Amazon waterways where it lives. It is an opportunistic predator, snatching anything small enough for it to handle in its strong jaws. Fish and crustaceans are its preferred prey and giant otters detect them with their keen eyesight, as well as sensitive whiskers that can sense the slightest variation in water turbulence.
Giant otters are social animals, forming small groups of between 5 and 10 individuals. Most groups are formed by parents, their offspring, and several young adults, with the females filling the dominant role. Giant otters display a number of social behaviors, including maintaining communal latrines and waiting for members of the group to finish feeding before moving on to a new area of water. Although giant otters are clumsier than other otters on land, they still spend their nights out of the water. They live in burrows dug into the banks of the rivers adjacent to their hunting grounds.
Numbers of giant otter in the wild have steadily declined over the past 50 years, mostly due to hunting for pelts. It is now illegal to kill a giant otter in many areas, but illegal poaching still occurs in areas of the Amazon. Deforestation and industrial pollution of the Amazon waterways have further contributed to the decline of these massive aquatic mammals. They are now the rarest otters on Earth.