Water shrew

Water shrew

©Geoffrey Kinns

Water shrew

Scientific name: Neomys fodiens
The large, dark grey water shrew lives mostly in wetland habitats. It's a good swimmer that hunts for aquatic insects and burrows into the banks.

Species information


Length: 6-9.5cm
Tail: 4.5-8cm
Weight: 12-18g
Average lifespan: 1-2 years

Conservation status

Protected in the UK under the Wildlife and Countryside Act, 1981.

When to see

January to December


The water shrew is our largest shrew. As the name suggests, it lives almost entirely in wetland habitats, such as streams, ponds, fens and reedbeds. It spends much of its time hunting for invertebrates and even swimming underwater to catch caddisfly and mayfly larvae. Although it doesn't have webbed feet, stiff hairs on its back feet and tail aid swimming. Water shrews live in small burrows in the banks of their watery habitats. They breed throughout summer, producing three to fifteen young per litter.

How to identify

The water shrew is a large shrew, with a silky, dark grey or black back and white underside. It has large hind feet and is the only shrew that is likely to be seen in the water.


Widespread, but absent from the Channel Islands, the Isles of Scilly, some Scottish islands, the Isle of Man and Northern Ireland.

Did you know?

The water shrew is quite unusual among mammals because it has a venomous bite. The poison in its saliva is strong enough to immobilise frogs and small fish. It can tackle prey up to 60 times heavier than itself, including newts, frogs, crustaceans and snails.