The Pyrenean desman is 11 to 14 cm (4.3 to 5.5 in) long with a rounded scale-covered tail of 12 to 16 cm (4.7 to 6.3 in), and weighs 35 to 80 g (1.2 to 2.8 oz).[3] They have a long, sensitive nasal trompe provided with hypertrophic vibrissae and chemo-/mechanosensitive Eimer's organs helping prey detection, and large webbed feet with fringed hairs to increase the swimming surface, and can close off their nostrils and ears to stop water penetration.[3][5]
The desman's body is covered in dark, brownish fur, with the exception of its tail and nose. The nose is black and is covered in vibrissae (facial hairs), which it uses to feel the movement of prey as it sticks its nose into mud or crevices while searching for food. The Pyrenean desman can live at least 3.5 years. The animals are mostly nocturnal, and eat small invertebrates, mostly aquatic macroinvertebrates. They breed up to three times a year, with the period of gestation lasting around thirty days.
