May 19, 2007 3 min read

When winter’s snow melts in the spring, I always notice a maze of small tunnels through the matted blades of grass in a number of areas of my lawn. Whenever I see them, I know the local shrew population has had an active winter.

Seven species of shrew are found in Pennsylvania, but the short-tailed shrew, Blarina brevicauda, is the most common.

In my garden it is the only species I have seen.

Of course, they are so small, one rarely gets to see a shrew at all.

A short-tailed shrew’s head and body together measure only 3 to 4 inches long. Because of their size, they are often mistaken for mice, but their short tail and lack of visible ears should preclude that. Even the eyes are small – sometimes to the point of not being obvious, either.

Shrews have pointy snouts and cylindrical bodies. The short, dense, velvety fur is lead gray in color and lighter on the belly. Shrews have five toes on each foot, and their teeth have a dark brown pigmentation.

Short-tailed shrews are not rodents, they are insectivores, and they are among the few mammals in the world that have poisonous saliva, which helps them immobilize their prey. (The toxin can cause a painful reaction in humans.) The shrew’s main bill of fare includes earthworms, snails, slugs, insects, other invertebrates, and sometimes small vertebrates, such as mice. It is not uncommon for these shrews to “store” their paralyzed victims alive for later eating.

That may seem rather harsh, but a shrew’s daily activity is an ongoing search for food, as these little animals have the highest metabolic rate of any mammal in North America. They must eat their weight in food each day, or die. I’ve read that shrews can die from hunger in less than half a day.

Finding their food is a bit of a challenge, perhaps. Shrews don’t have good eyesight. They rely on smell, their sensitive whiskers, and a form of echolocation to navigate their way around. They travel through borrows or runs of other small animals, or they make their own at or near the surface of the ground. Because they do not hibernate, in winter they burrow under the snow along the surface of the ground. Perhaps this need to survive fuels the short-tailed shrew’s aggressiveness. When encountered, short-tailed shrews, for their small size, are truly ferocious.

Short-tailed shrews can be found in many habitats, including but not limited to forests, grasslands and weedy fields. Their home range may span up to an acre, but many shrews can live in the same area-as the number of shrew tunnels in my garden obviously suggests. They communicate by clicks and squeaks.

Short-tailed shrews can produce three to four litters of young a year, spring through fall; usually 6 to 8 babies the size of honeybees per litter. They only live one to two years.

While they may be marginally annoying in my garden-what with all the tunneling and such-I don’t mind having these voracious little fur balls around, as long as they eat the bugs and slugs I don’t want. Besides, the animals most likely to eat short-tailed shrews would rather not. Shrews have scent glands on their flanks and rumps that make them unpalatable, though it does not seem to deter my chickens, who eat shrews when they can catch them.

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Susan Brimo-Cox gardens, observes nature and writes in Ohiopyle. Readers can send questions or comments to her at naturesgarden@brimo-cox.com.