10 - Shrews hunting under leaf litter
If you're out for a winter walk in the woods when the wind is calm and the sun bright - and if you listen carefully and quietly - you'll probably hear the soft rustling of nearby leaf litter. This is usually the only trace of shrew activity that most people ever experience.
Shrews are tiny, mouse-like animals whose short lives are lived completely in fast- forward. Of the 27 described species of shrew found in North America three of them call this corner of North America home. And while superficially resembling small mice these tiny mammals are classified as Insectivora, along with their brethren the moles and bats, and they live life at a frantic pace. Unlike most other mammals that can miss an occasional meal with no ill effects, a missed meal for a shrew means death. Their metabolic rate is so high that they're compelled to eat up to twice their weight in insects each day just to keep their metabolic fires stoked.
The insectivores are considered the most primitive of the placental mammals and shrews are considered the most primitive insectivores. When dinosaurs were blundering around the earth as lords of all they surveyed, shrews were down in the leaf litter doing what shrews have always done - looking for their next meal.
This constant quest for food has molded the shrew into a highly aggressive little terror of the insect world where they routinely attack and overpower insects larger than themselves. They're helped in this endeavor by being endowed - alone among our mammals - with venom produced by their salivary glands that is extremely toxic to invertebrate life. Of course this time of year, with adult insects on the scarce side, they're looking for worms and hibernating insects and their larva. But their quest is relentless and never ending so the odds of a quiet bystander catching their rustling of the leaves is very good. Keep your ears open.
Our three shrews
We have the Southeastern Shrew, Sorex longirostris, the Least Shrew, Cryptotis parva, and the
Shorttail Shrew, Blarina brevicauda
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Copyright © 2009 Ruby Jung
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