St. Lawrence Shrew (Sorex jacksoni)

The St. Lawrence Shrew

The St. Lawrence Shrew (Sorex jacksoni) is commonly mistaken for a rodent, as they slightly resemble mice. They actually belong to the insectivore family, which consists of small mammals that feed on insects. Because of their severe isolation, not much is known about the St. Lawrence Shrew.

The St. Lawrence Shrew is found only on St. Lawrence Island in the Bering Sea. Shrews tend to make their homes in the undergrowth and groundcover in forests, hiding and foraging among the leaves and plant materials.

Shrews are tiny, considered one of the smallest land-dwelling mammals on the planet. They typically grow to approximately 3-6.5 inches (74-158 mm) and only weigh 1.5-20 grams, depending on the variety. Shrews are covered in a thick, brown to gray fur with a pale to white underbelly. They have a pointy snout with small, sharp teeth that easily pierce their chosen prey. Their tails are very long, sometimes half of their entire body length, and they have very small eyes and nearly invisible ears. They don’t have very good eyesight and rely mainly on their hearing.

Shrews are essentially carnivores, feeding mostly on insects, but they will eat almost anything that they can easily subdue or catch. Many varieties of shrew have venom in their saliva. Shrews will often eat mice, spiders, or even other shrews, and they track their prey by the use of echoes. Sometimes, the high-pitched noise they emit will confuse and disorient their prey, making them easier to surprise and subdue.

Female shrews reach breeding age at around three months. The gestation period for a shrew is between 17 and 28 days, and the young are born blind and defenseless. They are nursed by their mother for about three weeks after birth. The female shrew can give birth to a litter of up to 10 young shrews. The optimal time for mating is between March and August. Shrews usually live only for about 12-18 months.

Shrews have active musk glands that produce an unpleasant scent, which is protection from many predators. Sometimes they are left by predators and not eaten because of this. Owls seem to be unaffected by this odor, and they hunt shrews regularly.

Further Information on the St. Lawrence Shrew:

E-mail info@unitedstatesfauna.com to add your St. Lawrence Shrew related website.

Bibliography:
Shrew. Encarta Encyclopedia, © 2000.
Tim Osborne. Shrews: Wildlife Notebook Series, © 1994. August 4, 2004. http://www.adfg.state.ak.us/pubs/notebook/smgame/shrews.php
AZGFD. Arizona Shrew © 2003. August 4, 2004. http://www.gf.state.az.us/w_c/nongame_arizona_shrew.shtml.