An evolutionary relic
The Russian desman (Desmana moschata) is one of two surviving species of the ancient Desmanini tribe of moles. Fossil records show that various desman species were once widespread across Europe during the Miocene epoch, which began 23 million years ago. The modern Russian desman is a relict species, an animal that has survived from a previous geological era and appears almost unchanged for millions of years.
Part of the mole family Talpidae, it is highly adapted for a semi-aquatic life in the slow-moving rivers and overgrown ponds of the Volga, Don, and Ural River basins. Its body measures 18 to 21 centimeters long, with a laterally flattened, scaly tail of a similar length that functions as a rudder. It has dense, waterproof fur, webbed hind feet for propulsion, and powerful forelimbs for digging burrows into riverbanks. The entrances to these burrows are typically located underwater, but the nesting chambers remain above the high-water line.
The desman's feature is its long, flexible, two-lobed snout. This proboscis is a highly sensitive tactile organ covered in thousands of microscopic sensory structures called Eimer's organs, which also cover the noses of other moles. Functionally blind, the desman uses its snout to probe the riverbed and detect the subtle water pressure changes created by its prey, which includes aquatic insects, crustaceans, mollusks, and small fish.
A mysterious decline
The Russian desman population has experienced a catastrophic collapse. In the mid-1970s, an estimated 70,000 individuals lived in the wild. By 2004, that number had fallen to 35,000. More recent estimates from 2020 suggest the population may be as low as 6,000 individuals, and in December 2023 it was uplisted to Critically Endangered on the IUCN Red List.
Historically, the desman was heavily hunted. Its thick, velvety fur was highly prized in the fur trade, and before World War I, as many as 100,000 skins were sold annually. The animal's name, moschata, refers to the strong musky odor produced by glands at the base of its tail, a substance once used as a fixative in perfumes.
Today, the primary threats are human-induced. Habitat destruction from the construction of hydroelectric dams, draining of floodplains, and water pollution has severely limited its range. The most acute modern threat comes from inexpensive and durable stationary fishing nets, often set illegally and abandoned. Desmans, which need to surface for air, get trapped in these nets and drown within 5 to 10 minutes. Competition and predation from introduced species, particularly the American mink (Neovison vison), have also contributed significantly to the desman's decline. Unlike native predators that are often repelled by the desman's musky scent, the invasive mink preys upon them directly.