Dave, the resident lab, and I are out for the usual reason in the yard behind the house. Dave is totally focused on a nearby tree, and I know why. A fox squirrel is sitting in its branches chattering away, scolding us for entering its world. It’s very noisy, and Dave stands, on point, entranced. Eventually, he decides that parktime needs are greater than squirrels, and he gets down to business.
Lots of fox squirrels, known as a scurry of squirrels, live in the trees around the house on Owl Acres. They scamper about stashing the black walnuts that litter the ground in late fall. They may stop to snack, sitting up on their hind legs, holding a nut in their forepaws and manipulating it with their highly flexible, sharp-nailed “fingers.” They’ll drill holes in the shell with their formidable incisors to get at the nut inside. If they’re not hungry, they’ll stash the nut or seed in a hole they dig in the ground. The hole is about an inch deep and the size of a quarter—the perfect depth for a walnut or an acorn to germinate in the spring. Then they’ll cover the nut or seed with dirt. They won’t remember just where they stashed them, but come winter, their keen sense of smell will help them find the nuts even if they’re buried beneath the snow. What they don’t find will sprout into tiny trees.
Like 40% of all mammal species, the Eastern fox squirrel (Sciurus niger) is a rodent. The term rodent comes from the Latin verb “to gnaw,” and that is what squirrels and all other rodents do. They all have four self-sharpening, chisel-shaped incisors in front which give them gnawing power. The incisors grow continuously. The fox squirrel’s front teeth can grow up to six inches per year. To keep them honed and at the proper length, the squirrel gnaws on things constantly. If something like an injury goes wrong with the alignment of the incisors, she’ll need an orthodontist and braces, or the results can be fatal. She won’t be able to eat. Like all rodents, squirrels have spaces on either side of the incisors they use to manipulate food. They also have a premolar and three molars in each quadrant for chewing. This dental plan is characteristic of all 2,000 plus species of rodents, from beavers to mice.
Unlike other species, the Eastern fox squirrel has orange teeth and red-orange bones that fluoresce in ultraviolet light. This coloring is due to a buildup of a substance called “uroporphyrin I” or heme, the pigment that makes blood red. Normally a specific enzyme (uroporphyrinogen III), breaks it down, avoiding toxic build-up and the reddish coloration. When this enzyme is not present in sufficient levels, though, the result is serious health issues leading to death in most species. In humans, the condition is called Gunther’s Disease and afflicts about one in a million people. In Eastern fox squirrels, however, the lack of this enzyme and consequent build-up of heme apparently has no ill effects if you don’t count fluorescing orange teeth. The mystery yet to be solved is how fox squirrels have adapted to the conditions which cause Gunther’s disease to the point that they have no harmful symptoms and live long and busy lives.
The word “squirrel” comes from ancient Greek meaning “shadow tail.” And truly the squirrel’s long bushy tail serves a multitude of purposes for the little rodent. It flips it up over its back as a shield from rain or summer sun. In winter, the squirrel uses it like a blanket, spreading it over itself to keep warm. It’s a stabilizer or a parachute when the squirrel jumps, and a rudder when it swims. And it’s a signal flag, sending a variety of messages to the neighbors.
The fox squirrels on Owl Acres wear a coat of rusty gray, with an orangish-yellow belly and chest and foxy orange accents on the tail. Big black eyes set on the sides of their heads give them a wide view. They have pointed stand-up ears, and the sensitive whiskers on their pointy noses compliment vision and hearing in exploring the world. They range in size from 17 to 21 inches long, about half of which is that big bushy tail. They weigh between one and two pounds,—about the size of a small kitten. On average, they live about six years in the wild if they avoid predators like foxes, owls, hawks and snakes.
Our squirrels are very versatile climbers and can jump horizontally up to 15 feet. They are also very fond of bird feeders. For these reasons, when we put up our new feeder station this fall, we added a baffle to keep them from climbing to the bird seed, and placed it far enough away from the house that they couldn’t jump to it from the roof. So far so good.
Meanwhile they’ll aerate the yard and plant hundreds of trees, most of which will meet the mower next summer.
Photo by Andrew C