An Ice Age Original
The Pyrenean desman, Galemys pyrenaicus, is a semi-aquatic mammal of the mole family, Talpidae. It is one of only two surviving desman species in the world. This small insectivore measures around 11-16 cm long, with a tail of a similar length, and weighs between 50 and 60 grams. Its distinctive feature is a long, flexible, trunk-like snout used to find prey underwater. The animal has dense, waterproof fur, large webbed hind feet for swimming, and strong forelimbs with claws for climbing and digging. Its small eyes give it very limited vision; it navigates its world almost entirely through touch.
The desman's snout is a highly developed sensory tool. It is covered in sensitive whiskers and specialized tactile receptors called Eimer's organs, which allow it to detect the subtle movements of prey in the riverbed. This anatomical feature enables the desman to hunt effectively in the dark, fast-flowing mountain streams it lives in. It can also close its nostrils and ears to prevent water from entering while submerged. The desman is primarily nocturnal and solitary, a secretive animal that is rarely observed directly by humans. Researchers often rely on camera traps and environmental DNA to confirm its presence.
A Declining Specialist
The desman lives exclusively in cold, fast-flowing mountain rivers and lakes, primarily in the Pyrenees and other mountain ranges of the Iberian Peninsula. Its presence is is a reliable bioindicator of high water quality, as its prey consists mainly of aquatic insect larvae—such as those of mayflies, caddisflies, and stoneflies—that are sensitive to pollution. The desman forages along the stream bed, probing silt and gravel with its snout to locate food.
The International Union for Conservation of Nature (IUCN) classifies the Pyrenean desman as Endangered. Its populations have experienced significant declines, with some estimates showing a reduction of over 50% in parts of its range. The primary threats are human-caused habitat destruction and fragmentation. The construction of dams and hydroelectric plants alters water flow and isolates populations. Water pollution from agriculture and industry degrades the pristine habitat the desman requires, and the introduction of the invasive American mink (Neovison vison) has created a new predatory threat.