Monday, October 1, 2012

The Continuing Saga of Squirrels and Walnuts

*** Starting this week my UVM students will be posting occasionally in response to the prompt: Find something in the woods that you've never seen before and figure out what its story is. So look for that!

What: Last week Clay and I found a dead gray squirrel (Sciurus carolinensis) on the sidewalk. It was a pretty good mystery as to how the squirrel had died. I skinned it with my Crow's Path kids and before we did the autopsy we couldn't detect any broken bones from getting hit by a car (plus it was about 10' from the road). The squirrel was a full grown male (just about the most enormous squirrel I've seen), and we thought maybe it could have eaten poison from a nearby house, fallen out of a tree, got hit by a bike or chomped by a cat/dog. We couldn't find any evidence of blunt trauma from getting hit by something, but when we pulled the skin up above the neck we could finally see two chomp marks that hadn't pierced the skin (so no external blood) but were most likely what killed this little critter.

You can notice in the two photos below the difference between the rear (left) and the front feet (right). The difference in color is due to the constant assault of the squirrels on the walnuts (see my previous post on how it stains their face and paws). I love looking up close at squirrels to see all the little differences between individuals, and this little guy, with a lone black chin hair popping out, was no exception. It also had orange staining its whole belly, probably from eating walnuts and then grooming its belly (around its crotch was particularly orange, which was amusing).

Ecological notes: With the kids we noted that the rear foot was flexible in almost all directions and could rotate just about 180 degrees. I was telling the kids that the squirrels will hanging from a tree hanging down with their feet rotated back behind them. I've also noticed that when they leap to a branch they rotate their feet so that they're hanging below their body and the bottoms are facing the direction they're going. As they hit the branch their rotated feet catch their body and grip onto the branch as they then rotate around to face forward and propel them in their next jump. Amazing! Another thing to note is that animals have larger feet where they hold most of their weight. Gray squirrels hold most their weight in their butts, so have larger rear feet. Same with raccoons, possums, beavers, etc. Dogs (think about pitbulls here) have larger front feet to support their broad chests and big torsos.

Where: Burlington

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