The giant river otter (Pteronura brasiliensis), also called river wolf, is a carnivorous mammal found only in South America. It is the oldest member of the weasel family (Mustelidae), and one of the largest predators of the Amazonian forests. Adults reach a length of about 2 meters. The river otters are brown with a yellowish-white spot on their throat, which is unique to each individual. They are a very noisy and gregarious species, which forms groups of between 5 to 10 individuals (Tirira, 2017). Otters spend much of their time in the water and have many adaptations that allow them to lead an aquatic lifestyle, such as the long whiskers that help detect underwater fish and the dense fur that water can not penetrate. They build their nests on the banks of rivers and lakes, where they sleep, give birth, and take care of their offspring.
The giant otter is cataloged as a Critically Endangered (CR) species, according to the Red List of Ecuador, and as an Endangered (EN) species on the IUCN Red List. During the 1950s and 1960s it was hunted extensively due to the value of its skin, until it was brought to the brink of total extinction. The giant otter faces many threats including habitat loss, habitat degradation (i.e. water pollution), loss of prey base due to overfishing, illegal hunting for their pelts, hunting by fishermen who see them as competitors, and increased exposure to diseases, like canine distemper.
Ref: Tirira, D. G. 2017. Guía de campo de los mamíferos del Ecuador. 2a. edición. Asociación Ecuatoriana de Mastozoología y Editorial Murciélago Blanco. Publicación especial sobre los mamíferos del Ecuador 11. Quito.