Squirrelly –adjective; eccentric, cunningly unforthcoming, reticent, odd, crazy, unpredictable, jumpy, restless or nervous…….a pretty unflattering description all things considered.However, the adjective actually describes behaviors that with respect to evolution are extremely advanced.
The squirrel’s bizarre zigzag / double back flight from danger seems random and indecisive, but is brilliantin light of millions of years of evolution against“death from the sky”. Once a raptor has committed to a strike, there is very little that can be done to change direction, successfully dodging this threat yielded more zigzagging squirrels. Unfortunately, this strategy actually makes them more vulnerable to cars, dogs or cats.
Evolution gave squirrels large eyes that are high on the skull to provide an extremely large field of view; just what a tasty morsel needs to evade being someone’s dinner. Unfortunately,this eye placement severely limits frontal vision and depth perception. To compensate, squirrels constantly scan for threats and perform complex “bob and weave” behaviors to triangulate distance.
People sweat, dogs pant and squirrels get wet feet. Locating sweat glands on their feet, between the foot pads and on their paws between the toes seems an odd manner to regulate temperature, but in combination with scent glands,it allows the squirrel to constantly lay down a scent trail, thereby claiming all they touch. Squirrels also appear to lovingly rub nuts on their face before caching. What appears as a cute behavior actually allows scent glands on the cheeks stamp the nut as “mine!”.
A large proportion of the brain is dedicated to spatial memory. Contrary to folklore, squirrels really do remember most of their cache locations (and I can’t even find my keys!) This spatial memory also comes in handy to move without pausing through the canopy.
Eastern Gray Squirrel
Blessed, or perhaps cursed with a high metabolism, squirrels preferentially select nuts and seeds that are high in protein and fat. Squirrels can’t digest cellulose, so they can’t graze like rabbits or deer. Early spring is the hardest time of year because stored nuts have been eaten, rotted or sprouting, but new sources are not yet available. While they appear to be vegetarian, squirrels adore a nice crunchy June bug or cricket. Prone to metabolic bone disease, squirrels are drawn to sources of calcium. Small prey, chewing on bones or shed antlers provide this necessary mineral.
Since squirrels do not form packs for cooperative hunting,it is surprising they have evolved extremely sophisticatedmeans of communication. Body language is a large component (especially tail flagging) of this communication, but squirrels also have a huge range of vocalizations, many of which are mistaken as birds or insects.
Many (including myself) mistakenly call the fox squirrel a “red” squirrel. American Red Squirrels (Tamiasciurus hudsonicus) exist in mostly in the northern third of the United States and Canada and are much smaller than either the fox or eastern gray squirrels, but bigger than a chipmunk. Soooo, if you’ve always called fox squirrels, “red” – just mentally substitute as you read along.
Rarely are squirrels observed swimming, but swim they do and quite well at that! A startled rehabilitator discovered just how well they swim when a recently released Ike survivor crossed paths with the big yellow dog that was “guarding” the pool. Panicked the squirrel would drown (or the dog would jump in after it) she grabbed a cleaning net only to watch it swim across the pool, jump out and scoot through the fence! Many swimming pools inadvertentlybecome death traps. To prevent a tragedy,simply leave a temporary ramp that will allow the animal to easily climb out.
The large leaf-lined nest that squirrels build is called a drey. Litters are born in the spring and fall and vary in size from one to six, but are usually three or four. Gestation is about 44 days and the young are born almost embryonic in appearance,pink and hairless with closed eyes and ears. Ears open after a couple of weeks, eyes two to three weeks later. By the time eyes are completely open and focusing well at six to seven weeks, the baby is already two-thirds the size of mom and will start moving around the limbs near the drey. Mom will take her babies to forage about the time she starts to wean at ten to twelve weeks of age.
Hypothermia can kill babies that fall from their drey, even in the heat of summer. Unless the baby is warm to the touch, it needs a source of heat. A drink bottle filled with hot water or a rice filled sock which is heated in the microwave can provide warmth for an hour. Place the baby in a small box that is placed near the tree for the mother to retrieve. Give mom an hour or two. Do not try to feed or give fluids to the baby. After Hurricane Ike many squirrels were cared for by well meaning people that caused potentially fatal inhalation pneumonia.
Both the eastern gray and eastern fox squirrel are diurnal, peak activity is early morning and just before sunset. Southern flying squirrels are nocturnal and are rarely seen before deep nightfall. They often go undetected because they are small, quiet and secretive.
Even if you never see them, proof that flying squirrels are nearby can be found in their unique method of eating whole nuts. Flying squirrels gnaw a small circular hole at the pointed end of the nut and scoop out as much as they can before moving to the next. Regular squirrels smash whole pecans and acorns, leaving shards everywhere.
Naming squirrels by their coat colors can often be misleading since both the gray and fox can vary from an almost white blond to coal black. Colonies of black squirrels exist in the northeast, mid-west, down the Appalachian Mountains and across the upper gulf coast. New Mexico and California also boast of colonies. The Heights in Houston even have a colony! Scientists have found that black squirrels arise from a single mutation and the mutation is dominant. Squirrels that homozygous (received a mutated gene from both parents) are a deep glossy black, while the heterozygous (received one mutated gene and one normal gene) show other colors (brown, red or silver) evenly distributed in the coat.
The eastern fox squirrel is on average thirty to fifty percent larger than the eastern gray, but without the other to compare to, size is relative. Weight is highly proportional to diet, but,eastern fox squirrels are usually a really heavy two pounds, pushing three; while the eastern grays are usually over one pound, but rarely over two. Their coat color is similar, but the tail and belly are strikingly different. The tail of a gray will be twitching and flashing so much it may be hard to appreciate the beautiful bright silver that tips each hair, the fox will probably be munching on something with its tail calmly curled against its back so it will be easily seen that each hair is tipped in rich reddish brown. The belly of the eastern gray ranges from bright white to a warm creamy white; while the fox has a belly that ranges from a warm light tan to almost orange.
The biggest difference between the two sub-species may be temperament. The fox is more laid-back and timid while the eastern gray is energetic and bold. The eastern gray is much more sociable and can often be seen chasing each other up and down a tree, across the canopy and down another tree. The extreme acrobatics of the gray squirrel can be breathtaking.They will chide intruders from a safe distance, cussing a blue streak and flipping their tail so fast it’s a wonder that it doesn’t fall off. When threatened, they will bolt up the nearest tree to chide or race through the canopy.
Black morph of Fox Squirrel
The fox squirrel tends to be more of a loner, they don’t seem to mind other squirrels nearby, but they aren’t going to waste energy with aerial acrobats unless it is breeding season. They tend to freeze and hunker down in the face of an intruder. When threatened, they will run up the nearest tree and again freeze to prevent detection. Fox squirrels are much more likely to be heard making soft, happy grunting/snuffling sounds as they forage.
Fox and gray squirrels appear to peacefully coexist – more or less. They rarely interbreed and when it happens the offspring seem physically inferior.Territories that are not in transition tend to be all fox or all gray. Where both are seen, it is usually the smaller gray that is moving into the fox’s territory. There is no obvious battle for territory; however, the bolder gray almost always eventually squeezes out the less aggressive fox.