MAMMALS OF THE BALTIMORE-WASHINGTON DC AREA
METROPOLITAN  NATURALIST
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Short-Tailed Shrew (Blarina brevicauda)

The Northern Short-tailed Shrew is common throughout the Baltimore-Washington area. I have found them in woods
and fields throughout our area, and have even found them in backyards in Baltimore City and the suburbs of
Washington DC. They are very secretive animals, making runways on the surface of the soil underneath leaf litter and
under grass or other plants. They eat insects, small animals such as mice and voles and probably even other shrews.
They also will eat seeds. They are fond of peanut butter and have been reported to eat the seeds of pine trees.

This is one of the few poisonous mammals in the world and the only one known to be poisonous in our area. The
saliva of the Northern Short-tail Shrew contains neurotoxins which immobilize its prey. The Short-tail Shrew eats
insects, earthworms, other small mammals, and small reptiles. The bite is relatively harmless to humans, it is said to
cause some pain and swelling. But to an insect or small reptile, amphibian, or mammal, a toxic bite from a short-tailed
shrew can cause paralysis or even death.

At least two toxins have been isolated from the saliva of the Short-tailed Shrew. Both of these toxins show some
potential for medical use.

A small peptide called soricidin was shown to have a paralytic action, acting by blocking the neuomuscular junction. A
patent application has been filed for this peptide as it might have medical uses as an analgesic or neuromuscular
junction blocker.  It has been suggested that the peptide might be useful as a substitute for botox in reducing
wrinkles. More detailed info can be found in the patent filings at
http://v3.espacenet.com/textdocIDX=WO2004046178&CY=gb&LG=en&DB=EPODOC.

A glycoprotein called blarina toxin has also been isolated from the shrew's salivary gland. This compound is being
investigated for its potential medical use in lowering blood pressure or aiding circulatory problems. Blarina toxin was
described in the Proceedings of the National Academy of Science (
Kita, M et. al., Proc. Natl. Acad. Sci. U.S.A. 101,
7542-7547 (2004) ).

Short-tailed Shrews appear to have very poor eyesight. They navigate and apparently locate prey by echolocation,
similar to the method used by bats. Many times while walking in the woods I have heard a shrill call as a small animal
scurried off under the leaf litter. The shrill call gives away the identity of the small animal as a shrew. I often wonder if
the call is used as much for echolocation as it navigates an escape route, as to startle a would-be predator.

The Short-Tailed Shrew can be distinguished from most of our other shrews by its short-tail, slate grey color, and size
(greater than 3 inches in length for an adult). The only other shrew in our area that has a short-tail, the Least Shrew
(
Cryptotis parva), is smaller is size (less than 3 inches in length) and generally a brownish color.
This cat had caught and killed this shrew when I came across it. Even well fed house cats will hunt and kill small
mammals and birds. Cats are very efficient hunters and can take a toll on shrews and other small mammals, as well
as birds and reptiles, when allowed to roam freely outside.