WESTCHESTER COUNTY, N.Y. – The squirrels in your yard are on a do-or-die mission: Fatten up against the coming cold and bury enough seeds and nuts to last until spring. They can’t guess how cold or mild the winter is going to be – all they know is that they have to create a food stash and make sure that other squirrels don’t get to it first.
Squirrels are territorial but their land is hard to defend. You’ll see them chasing interlopers away but they cannot stop all intruders, so they must be ingenious. If they see another squirrel while they’re burying a nut, they might only pretend to bury it, or come back later and move it. They also hoard food in hundreds of different places – called scatter hoarding – so, if some of it is discovered, the thief will not get away with everything.
You might be surprised to learn how squirrels find the nuts later. Their tongues and teeth leave a special scent on the food, which they can detect even through layers of snow. They also have good spatial memories so they generally know where to start looking. Birds seem to have the same memory for places they migrate to and scientists think animals may produce special enzymes during winter or migratory periods to help them remember things.
Squirrels don’t bury the whole nut. They use their strong jaws and 22 teeth to crack it open, and then bury the meat. For this job it’s essential they keep their teeth clean and sharp.
A strong enamel coating keeps human teeth sharp, but squirrels don’t have it. Instead, they’ve evolved a way of brushing that maybe you’ve seen and wondered about. They take a small branch from a tree and, as they chew through its fiber, they turn their heads. That makes the branch rub against each tooth and clean its surface. After the cleaning, they use the branch to sharpen each tooth point. This exercise can last for an hour but must be done by each squirrel every day.
Next to its teeth, a squirrel’s most important body part is probably its tail. The tail gives the animal balance as it performs daredevil aerial movements along power lines and treetops, and can act as a parachute when it makes a misstep. Additionally, squirrels use their tails to make them look larger when engaged in territory disputes, as decoy when being chased by predators and as sunshade in summer and as a blanket in winter.
Scientists speculate that squirrels – around here, mostly Eastern grays – have been in North America for more than 37 million years, so they’ve got preparing for winter down to a science. When the cold comes, they’ll huddle in treetop nests for days at a time, coming out when the sun does to dig up some nuts.
Every year, they forget some of those nuts, which might grow up into trees over time. When you see a forest rejuvenating, squirrels have done some of the work.
John Hannan is director of development for Audubon in Connecticut.