The Wild Side: Living with the squirrels
This week I am writing about the McSquizzy clan. This family of squirrels is named after the sassy critter in the Open Season movies. We started with just McSquizzy, but this spring he fathered a whole clan which now occupies the oak tree dominating my yard. This massive old tree reaches over my deck, my house roof, my driveway, the boat and camper, you get the idea. Pretty much anywhere you navigate in my yard, you pass under this oak tree. The McSquizzys kept busy all spring, raiding our bird feeder and digging in our flower pots, but generally harmless stuff. But then, something changed-the acorns began to ripen.
Oak trees are slow growing hardwood trees. They have to reach 50 to 75 years old before they are mature enough to produce acorns. This granddaddy oak must be far older than that. There are thousands of acorns dangling from its branches. The McSquizzy clan works the tree from end to end, tirelessly running up and down every branch. Typically squirrels will nibble off a group of acorns and let them drop to the ground. Later, they will pick them up and cache them for the winter. This is way more efficient than running up and down the tree carrying one acorn at a time. They don’t want to wait for the acorns to ripen and drop on their own; then they would have to compete with everything else that wants to eat acorns. Plus, gray squirrels don’t hibernate, so they know they have to stash enough food to keep them alive all winter. This means they have to start early and work furiously.
Gray squirrels are very interesting animals. Their two front teeth, called incisors, begin growing far up in their skull, and grow continuously throughout their life. The total lifetime incisor growth might be more than four inches. Squirrels have to chew daily to keep wearing these teeth down.
Squirrels are the only mammal I know of that can run or climb down a tree head first. You may claim house cats can, but that is more of a controlled fall. Squirrels have a special adaptation to make this possible; they can rotate their back feet 180 degrees. Thinking of that in human terms, imagine if you were walking up a steep slope that keeps getting steeper. You start to have trouble keeping your balance. As you continue walking uphill, your feet rotate to the sides and eventually to the rear, so your toes are pointing backwards and you see your heels in line with your knees. That would be an interesting adaptation.
The squirrels also have a little built-in GPS mapping system, helping them remember where they stash every acorn. Later, they will track back to each bit of food as they need it, using their sense of smell to help when they are within a fraction of an inch. Gray squirrels are able to eat a greater variety of acorns than red squirrels because their digestive systems can better handle the tannins contained in some oak species’ acorns. This makes them very adaptable.
So the squirrels are scrambling around dropping acorns. It sounds innocent enough. However, they seem to be following me. When I was working on the boat, they dropped them in the boat. Sitting on the deck, standing by the fence, it doesn’t matter; they seem to work furiously right above me. I actually have to wear a hat because they have dropped them on me a couple of times while standing still. I don’t mean to sound paranoid. I am a scientist, so I develop a hypothesis and then test it. To date, my hypothesis stands: the squirrels are out to get me.
So, if you drive by and see me running erratically, making sudden, jerky movements, don’t be alarmed-I am probably just trying to outsmart the squirrels.
Jeremy Holtz is a wildlife biologist with the Wisconsin DNR in Rhinelander, and writes a weekly column in the Star Journal. To contact him, call (715) 365-8999.