Desmans sit within Talpidae, the mole family, and retain a mole's tiny eyes and heavy reliance on touch while having reversed the group's usual habitat. The hind feet are webbed and provide propulsion, the tail is flattened side to side and acts as a rudder, and dense fur traps an insulating air layer in cold water.
The snout is long, flexible and covered in sensory structures, and it can be moved independently to probe silt and vegetation. Desmans forage on aquatic insect larvae, molluscs, crustaceans and small fish, and enter their burrows through underwater openings, which keeps the chamber inaccessible to most predators.
The animal's decline is the important current fact. It is listed as Critically Endangered, with habitat loss, water pollution, drowning in fishing nets and introduced muskrat among the identified threats. An estimated seventy thousand remained in the mid-1970s and about thirty-five thousand by 2004; later figures rest on irregular surveys across a large area. The only other living desman, the Pyrenean species, is also in trouble.