Studies on water shrew have suggested that they may have venomous saliva, which serves to immobilise the prey. Bites to humans produces a burning pain that may last for a few days.

Life span
Up to 14 months.

Statistics
Body length: 62-95mm, Weight: 10-22g.

Physical description
Water shrews have black fur above, with grey to black fur underneath. They have stiff hairs on the tail and on the hind feet to assist with swimming. Their teeth are red-tipped.

Distribution
They range throughout Europe, except for Ireland.

Habitat
Water shrews are typically found along the banks of clear, fast-flowing fresh-water rivers and streams, but they are also found by ponds.

Diet
They feed on a variety of aquatic and terrestrial invertebrates, including small fish and amphibians.

Behaviour
Water shrews are solitary but may live near to other individuals, and are more tolerant of each other than common and pygmy shrews. Their home range may be 60-80 square metres, including the water surface.

When diving, they are very buoyant due to the air trapped in their dense coat, and can only remain underwater for a few seconds. In still water they can dive to depths of 75cm.

They live in extensive burrow systems along banks, with an entrance above the water.

Reproduction
After a gestation period of 19-21 days, females give birth to 3-15 young, but average six. They breed from April to September, peaking in early summer. Females rear 1-2 litters a year. The young leave the nest after 24-25 days.

Conservation status
Water shrews are not considered to be endangered, although they may be threatened in Britain by loss of habitat due to pollution and disturbance. British shrews are protected by the Wildlife and Countryside Act 1981, and it is an offence to kill them without a special licence.