The tiny mammals known as shrews are sometimes mistaken for mice. Shrews are not rodents, however. Instead they belong to the insect-eating group of mammals called Insectivora, which also includes the moles. There are about 290 species, or types, of shrews.

Where shrews live

Shrews are found mainly north of the equator. They tend to favor moist habitats. Most shrews live on the ground and hide among grass and leaves, while others create burrows and live underground. They usually live alone, except when they are trying to mate.

Physical features

Shrews are among the world's smallest mammals. A variety called Savi's pygmy shrew has a head and body length of only about 1¹/₂ inches (3.8 centimeters) and a 1-inch (2.5-centimeter) tail. It may weigh less than a small coin. Many other kinds of shrews are only slightly larger.

Shrews are covered with thick, brownish gray, velvety fur. The skull is narrow, and a long, pointed snout overhangs the lower lip. The teeth are very sharp. A shrew's tiny eyes do not see very well, but a good sense of smell helps it find food and avoid danger.

Behavior

Some shrews are active both day and night, with regular periods of rest. Others are active only at night. Shrews are nervous creatures with very fast heartbeats. The shock of a loud noise or a rough touch can kill them. Because shrews digest food very quickly, they spend much of their time eating. Each day they consume at least twice their body weight in food. If insects are not available, shrews may eat one another to survive. Some shrews also eat plants. Others have poisonous saliva that can stun prey. This substance is painful but not deadly to humans.

Because of their tiny size, shrews are easy targets for other animals. Most mammals, however, will not eat shrews because many types have glands that give off an unpleasant scent. Some birds of prey and snakes do feed on shrews, however.

A female shrew gives birth to 2 to 10 young at a time. The babies are furless and blind but mature quickly. Most shrews live only for about one to three years.