Only three species of otter shrew are recognized. The Nimba otter shrew is nocturnal and semiaquatic. The giant otter shrew builds burrows among riverbank crevices. The Nimba otter shrew is a small bodied mammal. When traveling upstream the otter shrew travels on the bank and then swims downstream. The giant otter shrew is a mammal superficially similar to an otter in appearance. At this rate the Nimba otter shrew will be extinct between 2017 and 2020. The giant otter shrew ("Potamogale velox") is a semiaquatic, carnivorous afrotherian mammal. Contrary to its name, the giant otter shrew is not a true shrew (Soricidae).