Wednesday, December 19, 2012
Winter is a good time to find canned and bottled shrews.
Many walkers around here deem their daily communion with nature incomplete without the comfort of a brewski or two, and tossing the cans or bottles in the brush is apparently de rigeur.
Shrews are attracted to the containers at any time of year, but codgers can find them more easily in winter and redeem them for cash.
Nonetheless, it's been a coon's age since I've found a canned or bottled shrew.
So when I saw that can of Mickey's Malt Liquor tilted upward in the duff I went for it.
It had several ounces left in it, and I could tell there was something soggy in there too.
Sure enough, it was another Trowbridge shrew (Sorex trowbridgeii).
It was the right size and color, and the tail was bicolored, but in winter the wandering shrew (Sorex vagrans) looks quite similar.
The definitive identification had to wait until I could look at its 4 unicuspid teeth.
The photo doesn't do justice to the structure of the teeth, but it gives an idea of what you see under the dissecting scope.
Just keeping the wet shrew on the microscope stage while lifting the upper lip is a frustrating exercise, but that's what it takes to see the 4 diagnostic unicuspid teeth. Their relative size differs between species. The pigmented upper incisor is also slightly grooved.
Trowbridge and wandering shrews are the two common species I've found here.
Empty beer cans and bottles are not encyclopedias, but looking into them is a good way to learn about your local shrews.
Redeem them at your local recycling center, and you can actually get paid to learn about charismatic micro-mammals.