The gray squirrel is numerically the most common squirrel on the East Coast. Gray squirrels are also known as black squirrels, Carolina gray squirrels, cat squirrels, migratory squirrels, silvertails or timber squirrels. The Eastern Gray Squirrel has six distinct subspecies. (S.c... pennsylvanicus, S.c. hypophaeus, S.c. matecumbei, S.c. fuliginosus, S.c. extimus, and S.c. carolinenis) The subspecies Sciurus Carolinensis Carolinensis is the gray squirrel found in most of the south.
In general, there is no major difference between bucks and does in matters of coat color or size. Following Bergmann's rule, gray squirrels tend to be larger in the north than in the south. While not as large as the fox squirrel, the gray can weigh up to two pounds in weight in the North and be as long as twenty-one inches. In the South, they would normally be half of that weight.
A gray squirrel’s ears are longer and more pointed than the ears of a fox squirrel. Gray squirrels in the North grow heavy fur on their ears and the bottoms of their feet during winter. A gray squirrel has a pelage or coat made up of two type of hair. The fur is curly, fine and short and used to keep it warm in the cold winter. While the guard hairs are long, white and protect the fur. The long, white guard hair on the tail gives some of them a frosty or silver appearance and the name of silvertail. Their colors are a mixture of black, gray, and light-to-dark brown in a salt and pepper pattern. Their bellies and under legs are white to light gray light in color as is their tail. Individual specimens can be all black, all gray or all white. Colonies of black or albino squirrels exist in several states. There are albino colonies in Tallahassee, FL.; Olney, IL.; Trenton, NJ; and Greenwood, S.C. The gray squirrel will shed its body fur in the spring and fall but they shed their tail hair only in the summer.
Gray squirrels are more agile in trees than fox squirrels. They have several adaptations for arboreal life. They have parallax vision which is the slight distance that the eyes are separated and allows a squirrel to judge distances when jumping and squirrels can jump eighteen feet with their strong rear legs. Squirrels have color vision but are blue and yellow colorblind. They can see details very well and have the ability to recognize individual squirrels several yards away. The gray squirrel’s toes, which are longer and more flexible than a fox squirrel’s toes, are better for clinging to vertical surfaces. Some animals can only climb trees that they can get their limbs around but a squirrel can climb any tree no matter how large and when descending, the back legs can rotate one hundred and eighty degrees to allow the sharp, rear claws to hook into the bark. This allows the squirrel to be quite agile and move very rapidly in the trees even going down a tree headfirst. Watching squirrels has shown me that the gray squirrel develop habits. They will use the same trails on a regular basis to run rapidly through the trees.
A gray’s tail is not as plush or as long as a fox squirrels tail. The gray squirrel uses its tail as a shield when fighting, steering and balancing when running in the trees, as a blanket when cold or for shade when it’s hot. The movement and position of a squirrel’s tail can signal anger, curiosity, excitement, fear, and playfulness. If a gray squirrel’s tail has stripes it means that the squirrel is still adolescent, adult gray squirrels don’t have stripes.
Squirrels make three kinds of houses; winter dreys, summer dreys and dens nests. Winter dreys are large, round nests made of branches with their leaves attached in their outer layer located in a main fork of a tree. High enough to be safe from most types of predators but not so high as to be subject to continuous weather damage. The outside layer protects against precipitation, wind and cold and it is ten to eighteen inches in diameter. The inside cavity can be lined with soft organic material like feathers, fur, grass, leaves, moss, etc. any material that adds insulation and it is five to seven inches in diameter. Usually there are two openings. Summer dreys are also located in the upper third of mature trees about thirty feet up, but are not so elaborate in construction, sometimes they’re just open, flat platforms used for resting or eating. Dens are built in holes twelve inches deep and three inches across in over-mature trees, usually a deciduous variety like beech, elm, maple or oak, with holes that started from rot or woodpeckers. Dreys and dens are usually in trees that are touching each other in a stand; rarely do squirrels use isolated trees. In stands, the other trees act as windbreaks to stop the loss of precious heat in the winter, allow free movement from tree to tree when escaping predators, and are alternate sources of food which the gray squirrel can access with minimum exposure on the ground. Squirrels can but do not need to drink from streams and ponds. Their daily water requirements can easily be satisfied from eating succulent plant material or from dew. Both sexes make nests and a rough squirrel census can be taken calculating a squirrel for every one and a half nests.
In rural areas, squirrels can do severe damage. In fruit orchards squirrels can chew holes into the bark of various types of fruit trees to sample the sweet sap that starts to flow in spring, eat flower buds that normally would make fruit, destroy fruit before and after it ripens, and gird branches killing them off. This doesn’t count the small branches they chew cleaning their teeth. Squirrels eating fruit wouldn’t aggravate the owners so much if they really ate it all but they waste ten to fifteen times as much as they eat. In a hard wood forest, particularly New England, squirrels have been known to chew through pipes and container of Maple syrup especially plastic ones. In nut orchards, nut production is severely decreased because the squirrels harvest the large numbers of nuts before they’re ripe and carrying off a large portion of the remaining ripe nuts before the humans can start their harvesting. In the country at least you can shot and thin the ranks of the marauders and vent some frustration.
In the city, squirrels damage lawns by digging to bury or retrieving acorns, nuts, seeds and also in flower beds finding and eating roots and bulbs (Tulips, crocus, etc). They chew on ornamental shrubs or trees giving them a lop-sided appearance or sometimes killing the plant. They also eat flower buds before they open into blossoms. They take food intended for birds and will sometimes enlarge holes in birdhouse to enter and eat nestling songbirds. They travel on the power lines and short out transformers interrupting electrical power to large sections of the community.
Squirrels have been known to make nests in attics, garages, chimneys, barbecue pits, crawl spaces and other unusual places, even in cars. Any place that is dry, safe, and protected that they can squeeze their head through a squirrel can get into and make a nest. This is bad for several reasons; they mess up the insulation in the walls and ceiling, gnawing on electrical wiring can cause fires, they gnaw holes in the walls and allow precipitation to enter the house, etc… I have heard that you can buy a rubber snake and scare squirrels away or spray a pepper or a predator (raccoon) urine solution around your house to cause them to leave your plants and house alone or you can spend lots of money buying ultrasonic noise-makers to ward squirrels away. Of course this was said by the same people who recommend feeding garlic and yeast to your dog to repel fleas. Once the squirrel gets used to the sight, smell or sound they’re back again. LOL. The only practical way to remove squirrels is to check local ordinances and see if you are allowed to trap and relocate them at least five miles from your house. Plan ahead and determine the squirrel’s relocation prior to trapping it. I suggest someplace across a river and several roads. Even that may not stop its return, as gray squirrels are able to swim two miles in calm water. They swim using the dog paddle stroke with their heads and rumps, including the tail, held up out of the water. Myself, I think a skillet is the best and final answer for a troublesome squirrel. I would not recommend poisoning because in most places it is illegal, as there is no effective bait you use that wouldn’t be consumed by a pet or other animal.
Safety note: Place a towel over the cage when a squirrel is inside it and wear thick work gloves when handling the cage. When confined, squirrels become quite frantic and will careen around the enclosure possibly inflicting damage unto themselves. If possible provide water with sugar dissolved in it. When animals become stressed their blood sugar decreases dramatically and this could cause them to go into shock and die. After removal, seal the opening the squirrels used to gain access with flashing, quarter inch rat wire or mesh hardware cloth. You should cut back any branches touching the house. And stop putting out food for the birds for a month or more.
A squirrel has the jaw muscles and teeth to bite through the toughest nutshell to get to the food inside. They will spend over an hour each day cleaning all of their twenty-two teeth. The teeth’s cleaning is done by gnawing on branches and nutshells. As it bites into various small branches and exposes the fibers it will use these fibers much as we use floss to clean our teeth. The gray squirrel has two upper and two lower incisors that continuously grow at the rate of four to five inches in each year. The incisors are very similar to the fox squirrel’s incisors. This is followed by the premolars. The gray squirrel has two premolars following the diastema on each side of the upper jaw and one premolar on each side of the lower jaw. The diastema is a gap in the gums that normally would hold the canine or eyeteeth. The diastema allows squirrels to close off the back of the mouth by pulling in the skin on each side of the diastema. When it gnaws on bark, cones or nuts the small hard pieces are pushed out through the diastema and not swallowed. Baby squirrels are born with milk teeth that they keep until they are between six to twelve months of age. A male squirrel will spend twice as much time grooming itself as a female squirrel. They are one of the cleanest wild animals. Although a bite from a squirrel is cleaner than a bite from an opossum or raccoon, neither is recommended if you can help getting bit.
Gray squirrels usually have two mating seasons in a year; in mid-winter and early summer. The gray squirrel forms a pecking order usually with the oldest male squirrel as the top squirrel. There is a myth of red squirrels chasing gray or fox squirrels to castrate them. This is not true. This story came about because after the mating season in the fall, the testicles of fox and gray squirrels shrink so much in size that it looks like they have been removed. Also older squirrels during mating season will try to chase the younger males out of their territory and until they’re fully grown the young male’s testicles don’t descend. Squirrels rarely get into major fights among themselves. The worst fights occur when a female chases males away from her nest that contains her babies. She chases him nipping at his flanks to speed him on his way. Squirrels’ chasing each other is normal play behavior in a colony and males chase females until she decides to let him catch her. After mating the female chases the male away and she raises the litter by herself. If the doe did not protect her young, some male squirrels might kill the young to cause the doe to reenter estrus. The doe will prepare a nest of dry leaves, typically in a hollow tree. Eastern gray squirrel does as young as five and a half months old have been known to have pups. The gestation period is from forty-four to forty-six days. Litter size ranges from two to four pups; the winter litter is generally smaller than the summer litter. The average female produces six offspring each year.
A newborn pup comes into the world weighing less than a half-ounce, eyes and ears closed, naked, and with only their milk teeth. To find their mother until their eyes open at three to four weeks, gray squirrel pups depend on their vibrissae; four sets of whiskers around the nose, above and below the eyes, and on the bottom of the head in front of the throat; and their nose. The vibrissae are the same whiskers that a cat uses to find their way around in the dark. They are extremely sensitive to touch. In one week, the pups will normally double their birth weight. In three weeks the pup’s fur begins to grow and the ears to open. Their lower incisors start growing at three weeks and their upper incisors at four weeks, and when their chewing teeth erupt at six weeks, the mother decides they’re ready for weaning which will be complete by their ninth week.
After the tenth week, the juveniles live outside their mother’s nest and they learn the skills needed to survive; nest building, finding and storing food, and developing their muscles and coordination through playing. Young males leave the nests before the young females. Since the females stay at the nest until they’re more mature, females are numerically almost twice the population as male squirrels.
Gray and fox squirrels are non-territorial, unlike the red squirrels, and in areas of abundance overlapping territories and nest sharing without apparent conflict is not uncommon except during the mating season or raising young. Several squirrels may even occupy the same nest and even groom each other. This is noted more often in the winter but can occur throughout the year especially if there is a scarcity of nesting sites and a super abundance of food. This frequent contact increases the chance of spreading disease and parasites, especially fleas, internal parasites, ticks, and the mange mites.
Adult mange mites burrow into skin and lay eggs. After the eggs hatch, the larvae will crawl over the squirrel’s skin and burrow in at the hair follicles as they metamorphosize into nymphs. Heavy infestations of these parasites can cause squirrels to lose large patches of hair and increase the possibility of contracting a disease, which could be fatal if contracted at a time of famine, severe weather or stress from overpopulation and migration.
When young squirrels descend near to the ground they can become susceptible to warbles (bot fly larvae). They appear as lumps or large bumps that are normally located in the groin region with an ulcer or open sore but the warble can also occur at other locations also. Because of their small size, young squirrels can have a decreased ability in moving which makes them more vulnerable to predators. During periods of heavy infestations the squirrel population can actually be decreased due to the presence of warbles.
Squirrels, like most small mammals, have a short life expectancy. On the average, seventy percent of squirrels are killed in their first year. Each year after that will see half the survivors killed. Only one percent of squirrels will live to five years of age. The amount of squirrels killed by hunters is extremely small compared to other predators. That’s not to say that humans don’t have an impact on the squirrel population but humans have a higher impact in the city through automobiles running over young squirrels or electrocution by power lines and transformers. When a squirrel sees what is perceived as a predator, their first impulse is to freeze and hope they’re not noticed. If the "predator" continues in their direction, a squirrel will run an erratic pattern to elude capture. This works in the wild with a fox or bobcat because once a squirrel gets to a tree, they’re safe but on the city streets, this is not a successful strategy as evidenced by the thousands of dead squirrel bodies along the road. Squirrels running across the road have been clocked by police radar guns at speeds between fifteen and twenty two miles per hour. The second greatest impact on city squirrel population is dogs and particularly cats. Healthy adult squirrels are usually alert and active enough to detect and escape these threats. In the country, the greatest impact on the squirrel population is a combination of primarily lack of food, then disease, external and internal parasites, and severe weather. The predators that pose the greatest threat are birds, mostly; owls, hawks and eagles. Like the dog and cat situation, mature gray squirrels are less likely to be taken than the juveniles are. Other predators include bobcats, coyotes, foxes, raccoon, snakes and weasels. The raccoon and tree snake are the predators most likely to kill baby squirrels in the nests. Gray squirrels can live to sixteen years of age only if they’re very, very lucky.
During summer and fall, gray squirrels eat a third more than their body needs to prepare for the rigors of winter. This is in addition to storing food in the ground for future consumption. Like all tree squirrels, gray squirrels do not hibernate but are active throughout the entire year. You may not notice them as much in winter because during severe storms or extreme cold the squirrels may spend more time inside the nest to conserve body heat. But even during severe winter weather they will leave their nests to search for food. Because of their high metabolism (A squirrel’s normal temperature is between 101 to 102 oF), squirrels must eat their weight in food each week to stay active and healthy. Their superb sense of smell and memory are used to relocate the hundreds of food caches they buried during the harvest time in the barren times of winter. The most active times are two to four hours after sunrise and two to four hours before sunset depending on weather conditions. That adds up to approximately fifty to one hundred pounds of food a year for each squirrel. The gray squirrel’s diet consists of acorns, animal bones, antlers, berries, bird eggs, bulbs, buds, carrion, certain flowers, frogs, fruit, green shoots, inner bark, insects, mushrooms, nuts, pine seeds, roots, seeds, vegetables and even nestling birds though it’s less carnivorous than the red squirrel. Grey squirrels are often found in the city parks and around people’s houses near bird feeders.
When a gray squirrel finds a bird feeder they look upon it like a tree full of acorns. They don’t understand about ownership rights, they just see a lot of good food that needs to either be eaten or stored for winter. People may slow them down but through perseverance and ingenuity a squirrel will find a way to obtain entrance to the gastronomic treasure trove. Not bad for an animal with a brain the size of a walnut.
In the city, gray squirrels can become quite bold and will take food from a person’s hands. This is entertaining for city folk who rarely interact with many "wild" animals. But because the squirrel’s eyes are located on the side of their head and they are constantly on the "lookout" for signs of predators, they can’t really concentrate their eyesight on the food that they are eating and are likely to bite the hand that feeds them. If this happens wash the wound out thoroughly. Squirrels rarely have rabies but all wild animals have bacteria and germs in their mouth. Ensure the Tetanus shot is current. You should also seek medical advice from a qualified source about antibiotics and verification on whether the bite has been cleaned enough. An incident like this is very traumatic for little children, so always supervise feeding or playing with any animal, even the family dog.
The amount of salt a squirrel requires can be easily obtained in its diet and the extra amount of salt in snacks and salted peanuts can affect its heart, raises the blood pressure and increases its pulse. This tends to shorten a squirrel’s lifespan. This is not too dissimilar to salt’s effects on a human.
Due to changes in different tree species’ ability to produce bumper crops and small crops other years, a diversity of food producing trees is needed to maintain high populations. During consecutive years when trees produce outstanding mast harvests gray squirrel populations may explode and reach very high levels. When this is followed by a year of low mast production that cannot support the huge number of squirrels in that area, the squirrels will move in mass looking for new territory.
In the frontier days of America, primordial hardwood forests covered the land and were so extensive that a squirrel could travel from Florida to Maine and never set foot on land forming a perfect environment for the gray squirrel to flourish. Because of these favorable conditions, the squirrel’s population could swing extremely high at intervals of five to ten years. During one of these peak population occurrences when the squirrels were on the move it was stated that it took a month for the mess of squirrels to pass through an area (Robert Kennicott in his article "The Quadrupeds of Illinois" in The Annual Report of the Commissioner of Patents for 1846). While this gave the pioneers an incredible experience for conversation, they don’t call a group of squirrels a "mess" for nothing.
This huge number of squirrels can do an unbelievable amount of destruction to crops, trees, and farms through the squirrel’s eating, gnawing and excrement. During emigration, the huge mess of squirrels traveling through croplands devours the entire income that farmers were counting on to pay their bills and feed the family and stock through to next year. Even orchards are devastated by the squirrels gnawing on the tree’s rhytidome (outer bark) to get to the periderm (Inner bark). All branches above where the branch or trunk has been completely girdled will die as the periderm acts similar to our blood vessels to carry nutrients to the leaves and other living parts of the tree. Any holes gnawed through the bark make the trees susceptible to fungus and bacteria. In addition, the small terminal branches are the parts of the tree where fruit is normally produced and these are the parts that squirrel will chew on keeping the teeth clean. Whenever farmers tried to protect their crops or trees the very vastness of the horde prevented any true success. For every squirrel they killed by club, dog or gun, a hundred more squirrels showed up to continue the destruction.
Squirrel droppings or scat are rarely seen because they are very small, a little larger than grains of rice, are pale brown in color and they decompose very rapidly. But when you have hundreds of thousands of squirrels making a mess in the same area, the ground, trees and houses become covered with them. Think of snowflakes, hardly noticeable by themselves but when you have millions of them they can devastate tree branches, power lines, and houses. The poor farmers must have thought they were being tormented by a new biblical plague.
In the early 1840s, John Audubon and John Bachman traveled throughout the Eastern woodland, Missouri, the Rocky Mountains, along the Mississippi River as well as coastal regions of Florida to do field work for The Viviparous Quadrupeds of North America, a definitive record of mammals in North America. During the trip they noticed the emigrations of gray squirrel and record their observations as follows:
"This species of squirrel has occasionally excited the wonder of the populace by its wandering habits and its singular and long migrations. Like the lemming (Lemmus Norvegicus) of the Eastern continent, it is stimulated either by a scarcity of food, or by some other inexplicable instinct, to leave its native haunts, and seek for adventures or for food in some (to it) unexplored portion of our land."
Because of the numerous squirrel migrations, John Audubon and John Bachman were convinced that the squirrels on the move were a separate species from the gray squirrels and gave them the scientific name Sciurus migratorius.
Dr Hoy, who had experienced squirrel migrations in southern Wisconsin in 1842, 1847, and 1852, said the migrations occurred when the mast was exceedingly abundant and the squirrels in excellent condition. As Robert Kennicott observed in 1856, "The reason for these migrations is not satisfactorily explained. That they are caused by want of food is hardly probable, as the squirrels are found to be fat at the time, and as often leave localities abounding with food as otherwise."
The reason for the emigrations could be the stress of the large numbers of squirrels constantly interacting with each other causes them to "gets on each other’s nerves". Instinct could tell the squirrels that the home territory could not support their numbers that particular winter as the emigration occurs during the summer or fall before the effects of low mast production would be noticed. This emigration may take hundreds of miles before they can find a suitable new range. Emigrations differ from migrations because these emigrations are one way trips with the mess of squirrels traveling in mass in one direction and most of the squirrels that travel dying during the exodus. True migrations would be like the yearly flights of geese and other birds or animals that leave an area and return to it on a regular schedule.
One of the earliest referenced emigrations occurred in 1749 in Pennsylvania. Records show the state spending three cents for each squirrel killed. Over six hundred and forty thousand squirrels were turned in for the bounty. This accounts only for those turned in and does not consider those left in the woods and fields. It also does not count the immeasurable squirrels drowned attempting to traverse rivers or streams nor those killed by voracious mammals or birds. And several more thousands must have perished from simple exhaustion. A squirrel migration must have seemed like a fantastic banquet to the carnivorous beasts.
In 1807, when a squirrel emigration threatened agriculture in Ohio and knowing that bounties almost bankrupted the state of Pennsylvania, the state of Ohio passed a law stating that all taxpayers had to bring to the township clerks an amount of squirrel skins in proportion to their taxes. The amount varied from ten to one hundred. The law had little or no effect on the size of the squirrel mess.
Sometimes hunts were organized to control the massive influx of squirrels and bring their population back down to a manageable level. One hunt organized in 1822 killed almost twenty thousand squirrels. These hunts continued through the 1850s. In 1857, it was reported that a hunter killed one hundred and sixty squirrels in one day.
During modern times, squirrel emigrations have not been as spectacular because of the cutting and fragmentation of the vast hardwood forest does not normally allow the build up of the same size squirrel mess as previous eras. But in 1964, millions of squirrels emigrated from the north of Georgia to the south. "One squirrel was reported swimming across the Allatoona Reservoir and encountered a boat in his path. It didn’t stop him. He just ran up an oar, jumped in the boat, ran across the man in the boat, and jumped back into the water continued his swim south. Normally wild squirrels in the woods are scared of man but during migration they lose their normal fear.
In 1968, a migration of squirrels occurred in most of the eastern United States; Alabama, the Carolinas, Georgia, Maryland, New York, Pennsylvania, Tennessee and Virginia. In New York, one hundred thousand drowned squirrels were pulled out of one reservoir. The number of squirrels killed by automobiles was a thousand times as high as usual. Some estimates of the squirrels number went as high as eighty million.
In the fall of 1998, Arkansas had a "squirrel bonanza". Hunters reported reaching their limits unusually fast even when the weather conditions were far from ideal. Many drowned squirrels were reported on the shores of Bull Shoals Lake in northern Arkansas. The incidence of road kills was several times higher than normal.
In 1876, a few Sciurus Carolinensis were imported into Great Briton and released from various places like Woburn Abbey, in Bedfordshire. By the end of WWII, the gray squirrels had multiplied to such a large population that the British Forestry Commission was giving ammunition to shooting clubs and paying ten cents for each squirrel tail. That was big money and enterprising young boys fervently invested in slingshots and marbles and diligently stalked these urban vermin. It made little difference except it thinned out the careless and less intelligent young squirrels.
Today, over two and a half million gray squirrels are living in the British Isles and their numbers are increasing every day. They have replaced the British red squirrel (Sciurus vulgaris) in most of England, Ireland, Wales and the Scottish lowlands. The red squirrel population has dropped from several million to less than two hundred thousand. Partly this is due to the fact that the American gray squirrel can eat a wider variety of foods than the red squirrel can consume. Although both consume similar food; berries, bulbs, fruit, insects, nuts, vegetables, etc… the gray squirrel produces an enzyme that breaks down tannic acid and allows them to eat acorns from the red oak with no bad side effects. The red squirrel is not able to consume acorns from the red oak. The gray squirrel is also more aggressive in gathering food and more tolerant to the presence of people allowing them to utilize the food sources in the city that reds don’t have the audacity to pilfer. Some ecologists believe a virus (parapoxvirus) has significantly contributed to the demise of the red squirrel population. The American gray squirrels are carriers and are apparently immune to the effects unlike the red squirrels, which suffer one hundred percent morality in the wild. Symptoms are lesions and scabs on the face, feet, and genitals.
From England, the American gray squirrel was introduced into South West Cape, in South Africa by Cecil Rhodes where it has found the climate much to its liking. Gray squirrels have also found their way to Italy and other European countries where they are flourishing beyond appreciation.
The gray squirrel was also introduced into Australia in the late nineteenth century. They were found in garden suburbs in places like Melbourne but they died out several years ago. Australia is one of the few places that the gray squirrel hasn’t conquered. Yet!
People are divided in response to squirrels. Because gray squirrels easily adapt to the presence of people and are readily visible, those who enjoy watching nature view the gray squirrel as a likeable rogue who pilfers bird feeders but repays the owner with ample entertainment in the form of playful antics and behavior. Others feel antagonistic to this little "backyard bandit" and devise ingenious methods to thwart his stealing food meant for the avian community. But squirrels are very intelligent and can usually counter any strategy their opponents devise. They carry parasites and disease but they taste really good in the soup pot. And it’s hard not to admire an animal that when a dog chases them up a tree will stop and release upon the enemy a whirlwind of imprecations.
So, although I can’t speak for everyone but as long as the squirrels don’t get in my house or there’s no space in the freezer, I’ll enjoy watching the little bandit frolicking in my backyard.