Eurasian Water Shrew
Neomys fodiens
The Eurasian water shrew is a semi-aquatic mammal and the largest shrew species native to Europe. It features a dense, water-repellent coat and stiff hair fringes on its feet and tail that act as oars for swimming. It inhabits the banks of clean, oxygen-rich flowing and standing waters. Notably, it possesses toxic saliva, allowing it to paralyze prey such as small fish or amphibians. The species is strictly tied to aquatic habitats and maintains a solitary, territorial lifestyle.
Details
Identification
Black to slate-grey upper side, silvery-white underside with a distinct color boundary; fringes of stiff hairs on the hind feet and the underside of the tail (swimming keel).
Social behavior
Solitary and strictly territorial; territories are aggressively defended against conspecifics both on land and in water.
Diet
Carnivorous; feeds on aquatic invertebrates (caddisfly larvae, gammarids), snails, as well as small fish and amphibians.
Hunting strategy
Active underwater hunting via diving; prey is often paralyzed with toxic saliva and consumed on land.
Overwintering
Active during winter; does not hibernate and must forage continuously even in freezing temperatures due to its extremely high metabolic rate.
Ecology
Ecological role
Important predator of aquatic invertebrates; regulates populations of insect larvae and serves as prey for owls and herons.
Natural predators
Barn owl, tawny owl, grey heron, northern pike, trout, weasel, fox.
Competitor species
Mediterranean water shrew (Neomys anomalus), brown rat (juveniles).
Ecosystem service
Contributes to the biological control of insect populations in riparian ecosystems.
Threats
Water pollution, pesticide runoff, loss of natural riparian structures, drainage of wetlands.
Scientific profile
Profile
Distinguishing features
Fringes of stiff hairs on the hind feet and the underside of the tail (swimming bristles), red-tipped teeth (Soricinae), toxic saliva (blenina) to paralyze prey.
Habitat
Banks of clean, oxygen-rich running and standing waters with dense vegetation; also found in damp forests, bogs, and wet meadows.
Diet
Aquatic invertebrates (caddisfly larvae, amphipods), snails, small fish, tadpoles, as well as terrestrial insects and worms.
Protection & threats
Main threats
River engineering, loss of riparian vegetation, pesticide input from agriculture, water pollution, drying up of small water bodies.
Population trend
Regionally declining due to habitat loss and fragmentation; global population is considered stable according to the IUCN.
Conservation measures
Preservation and restoration of near-natural watercourses, protection of riparian buffer strips, reduction of pollutant inputs, habitat connectivity.