Giant otters once were found throughout the tropical rain forests of the Amazon, down to Brazil's Pantanal, the world's largest wetland . Today they are found only in the most remote waters in tropical South America. Hunting for their luxuriant fur, along with habitat loss, has reduced their numbers to an estimated 2,000 to 5,000. Giant otters live in lakes and slow-moving rivers in forested areas. They are perfectly adapted to their watery environment, with large, webbed feet and stout tails to guide them through submerged vegetation, and ears and noses that close when they dive in search of prey.
Giant otters are very social animals.
They live in extended families of perhaps ten otters. They hunt cooperatively and share babysitting duties. The groups respect territories and do not fight with each other. Each group's stable social structure is centered on the life-bonded dominant pair, which is the only pair that reproduces. The group raises one to four cubs annually.