Northern short-tailed shrew

Northern short-tailed shrews live mostly out of sight, in runways under leaf litter, in the tunnels of moles and voles, and in their own shallow burrows. They are active in bursts through the day and night and do not hibernate, hunting under snow in winter.

They are one of the few venomous mammals. Their saliva contains a toxin that paralyses prey such as earthworms, insects and snails, and lets them store living prey for later; it can also subdue mice. They are thought to use high-pitched clicks to help find their way through dark tunnels.

Short-tailed shrews eat large numbers of insects, larvae and slugs, including many that damage plants, and they are a regular food for owls, hawks, foxes and snakes.

They are also one of the best-studied venomous mammals, and the chemistry of their saliva has interested medical researchers looking at how its toxins act on nerves.

Breeding — spring to autumn, two or three litters a year
Gestation — about 21 to 22 days
Litter — usually three to seven young, born blind and hairless in an underground nest
Weaning — at about three to four weeks old
Independence — soon after weaning
Lifespan — rarely more than two years

• Cats catch many shrews and often leave them uneaten, because shrews taste unpleasant to predators.
• Leaving leaf litter in beds and under shrubs gives them hunting ground.
• A shrew's bite can be painful; use gloves or a container to move one out of a building.
• They sometimes enter basements and garages in autumn; a gap under a door is usually how.

• A shrew is a baby mouse or a young mole. Shrews are their own group, more closely related to moles than to mice.
• Shrews are harmful to gardens. They eat insects, grubs and slugs, not plants.
• A shrew left dead on the path was poisoned. Many are killed and discarded by cats and other predators that find them distasteful.

• Southern short-tailed shrew
• Least shrew
• Eastern mole
• Masked shrew