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.
In 2023 the IUCN moved the species from Endangered to Critically Endangered, citing an estimated 83 per cent fall over the previous decade; fewer than four thousand are now thought to survive in Russia, against roughly seventy thousand in the mid-1970s. Habitat loss, pollution, drowning in fishing nets and introduced muskrat are the identified threats. Survey coverage is patchy across a vast range, so every figure is an approximation. The only other living desman, the Pyrenean species, is also in trouble.