Giant river otters (scientific name: Pteronura brasiliensis) are an endangered species among the three top predators in the Tambopata River and its oxbow lakes (the other two being anacondas and caimans). They are piscivores, eating the fish that live in the river. Typically, groups of otters will have nine to twelve members. River otters are monogamous (mating for life), and live in groups, often composed of one or more “families.” A typical litter of river otters will have four pups. The pups that are born to a couple will stay with the parents until maturity (approximately two years), after which they will separate and go off on their own, looking for a mate and a new group. The average lifespan for a giant river otter is eleven years.
River otters are extremely territorial, and will fight with other animals in the river over territory, including caimans, anacondas, and even other giant river otters. When encountering other predators such as caiman in their territory, river otters will attack as a group, killing their opponent. For this reason, they are called “lobos del rio” in Spanish, which translates to “wolves of the river.” River otters will also fight with opposing groups of otters if they come into their territory; the “winner” of these fights can take over (or keep living in) the territory in question, with the “losing” group having to find a new place (or return to their old sanctuary).
Despite being one of the top predators in the region, giant river otters are very shy around humans. While some guides in the region have sighted them many times, tourists in Madre de Dios have a lower likelihood of seeing giant river otters.
– Maya Camargo-Vemuri