of the The Suppression of Active-Pattern-Recognition
January 16th, 2007
by Stan Goff
Where I live now, drivers are frequently obliged to stop in the middle of the street to avoid squashing squirrels. I live in North Carolina, and the Eastern gray squirrel has a scientific name, Sciurus carolinensis, that suggests I am living in their biological epicenter.
These rodents are â€” by best accounts â€” around 30 million years old, making them our great great great grandparents in evolutionary terms; and their adaptability to multiple climates, as well as urban landscapes, suggests they will be around long after we have figured out how to commit collective suicide. They are so thick in my own suburban neighborhood that we could harvest them for meat now without putting a dent in ther population. Our abundance of white oak trees sheds tons and tons of acorns each year â€” a squirrel staple â€” and squirrels are voracious omnivores, even occasionally indulging in cannibalism.
They have adpated through changing coloration almost before our eyes, with black varieties emerging in urban centers in our lifetime; but their behavioral patterns are more ancient inscriptions. Cars have been around for a century, more or less, with an explosive proliferation in the last 50 years. The result is a fatal mismatch.
Squirrel defensive patterns emerged to cope with other threats â€” hawks, owls, weasels, racoons, foxes, coyotes, bobcats, and big snakes. Today, we can add to that, dogs and cats; but they themselves are still behaviorally etched with hunting patterns they carry from their feral cousins. My own dog hunts them relentlessly in the back yard, and the squirrels win around 99 times out of a hundredâ€¦ whereupon they bark back at the enraged pooch from the trees.
What the squirrel has perfected over the aeons is a combination of deception and footwork that matches the predatorsâ€™ tactics.
When faced with a potential threat, the squirrel shifts her tail back and forth, flicking it in the same way a fisherman jiggles an artificial lure to attract the predatorâ€™s eye, or the way a bullfighter agitates a cape to deceive his victim. A squirrelâ€™s tail can be bitten off fairly easily, leaving the rest of the squirrel intact to live on; and predators typically orient on movement. Squirrels can even heat their tails up to fool pit vipers, serpants that orient on thermal signatures from their prey.
In conjunction with this tail-deception, the squirrel does a kind of rapid-rewind two-step dance as the predator closes in, weaving back and forth like a boxer to set up a repetitious pattern of oscillation by the predator. At the last moment, in a kind of rodent jui-jitsu, Sciurus carolinensis breaks the rhythm of the back-and-forth, and dives 45 degrees lateral to the accelerating predator. The charging animal overshoots the squirrel, and by the time she can turn to remount an attack, Sciurus has scampered up some vertical surface, whereupon she can leap from tree to tree, or roof to tree, or tree to power line, and make her escape.
Over 30 million years, the species itself has recognized a pattern and adapted its defensive tactics all the way into a fixed neural pathway. When the squirrels on my street see an oncoming car, this amazing adaptation fails. They are reacting to a conscious predator, and the car is neither conscious, nor a predator. Itâ€™s just a car. The Gotcha Two-Step that lets the gray squirrels run up trees to talk trash back to my mutt doesnâ€™t throw the car off at all. It is simply a terminal display without an audience, unless the driver sees the squirrel and slows down.