Neomys fodiens
Eurasian water shrew

Neomys fodiens occurs throughout Eurasia, to western Siberia, northern Asia Minor, the Pacific coast of Siberia, and North Korea.

Found on the banks of both standing or flowing fresh water and adjacent areas.

A darkly colored shrew with a white underside. Coloration on dorsal and ventral sides are sharply demarcated. A fringe of bristles runs along the ventral surface of the tail and on the paws which are thought to serve as a swimming aid. Teeth have red tips. Females have five pairs of mammae.

These shrew are solitary. If kept in captivity, individuals are both territorial and aggressive toward one another. They are generally active both at night and during the day, and they do not hibernate through the winter. One laboratory study found that shrews of this species mutually avoid one another much of the time, but when this does not work active antagonism can occur. They also seem to have no typical social hierarchy.

These shrews forage almost exclusively underwater, efficiently preying on aquatic invertebrates such as snails, mollusks, freshwater insects, and also small vertebrates such as fish, amphibians and frogs. Prey are weakened by a poisonous secretion from the submaxillary gland. They generally forage by taking a dive that can last up to 20 seconds. After coming onto land, water shrews quickly run into their burrows and emerge a moment later almost dry, after coming through the tight squeeze of the tunnel where the water is absorbed by the soil. The process is then repeated a few meters away along the stream bank. Water shrews are also known to eat some terrestrial insects as well, such as dipteran larvae.

No negative impacts known.

These shrews eat the larvae of insects which some humans find bothersome.

Quite common within its geographical range.

During dives, air remains trapped between the outer hairs of the thick coat of water shrews. This greatly increases the bouyancy of this shrew. In a laboratory experiment, a few tenths of a mg of the neurotoxic saliva killed a vole very quickly.