Thursday, February 2, 2012

An Insectivore

There are several species of shrew in Michigan, the most widespread and visible being the Northern Short-Tailed Shrew (Blarina brevicauda). Primarily nocturnal and active year-round, they can sometimes be seen darting across snow or shuffling through forest leaf litter. Due to their small size and secretive habits, however, shrews are more often seen as "presents" on the doorstep, thanks to a hunting cat or dog. Because shrews emit a foul odor, predators don't usually eat their them once they've been dispatched.

Despite being similar in size and appearance, shrews are not rodents. They are insectivores, primarily eating small invertebrates, though their diet includes mice and amphibians, as well. A rarity in mammals, short-tailed shrews secrete a toxin that paralyzes their prey.

Thanks to a friend's dog, I picked up a short-tailed shrew today. It's the first time I've seen one in several years, and I'd forgotten how soft and silky shrew fur is! Since this shrew was dead, its miniscule eyes were closed, which made locating them near to impossible. One of the most striking features of the shrew was its sharp, black-brown teeth:

In shrew terms, short-tailed shrews are pretty large – they're about the same size as a deer mouse. Still, everything about them is very tiny. Their relative, the Pygmy Shrew, is one of the smallest mammals in North America, and I can't imagine how small they must be. I used a macro lens to photograph this animal – any other lens wouldn't have done a proper job.

Shrew feet are actually kind of scary when viewed at a size several times larger than life! Their front paws are very strong, and are good for tunneling.

A shrew's nose is very sensitive, and is used for detecting prey. Because their eyesight is so poor, shrews also use their nose for finding their way. Helpful too are their long whiskers.

Read more about the Northern Short-Tailed Shrew here.

1 comment:

  1. Very high quality, thank you. I wouldn't call the Short-Tailed Shrew useless though!