Tree squirrels are the members of the squirrel family (Sciuridae) commonly just referred to as "squirrels". They include more than 100 arboreal species native to all continents except Antarctica and Oceania.
They do not form a single natural, or monophyletic, group; they are variously related to others in the squirrel family, including ground squirrels, flying squirrels, marmots, and chipmunks. The defining characteristic used to determine which species of Sciuridae are tree squirrels is dependent on their habitat rather than their physiology. Tree squirrels live mostly among trees, as opposed to those that live in burrows in the ground or among rocks. An exception is the flying squirrel, which also lives in trees but is distinguished from other tree squirrels by a specialized physiological adaptation: folds of skin called patagia that extend between the limbs and function as gliding surfaces, allowing the animal to glide between trees.
The best-known genus of tree squirrels is Sciurus, which includes the eastern gray squirrel of North America (introduced to Great Britain in the 1870s), the red squirrel of Eurasia, and the North American fox squirrel, among many others. Many tree squirrel species have adapted to human-altered environments such as rural farms, suburban backyards and urban parks.
Classification
Current taxonomy, based on genetic data, splits the tree squirrels into several subfamilies. The following genera of the squirrel family are classified as tree squirrels.
Subfamily Ratufinae Genus Ratufa (Asian giant squirrels) Subfamily Sciurillinae Genus Sciurillus (South American pygmy squirrel) Subfamily Sciurinae Tribe Sciurini (mostly American tree squirrels) Genus Microsciurus (American dwarf squirrels) Genus Rheithrosciurus (Borneo tufted ground squirrel) Genus Sciurus (Eurasian and American tree squirrels) Genus Syntheosciurus (Central American mountain squirrel) Genus Tamiasciurus (American pine squirrels) Subfamily Callosciurinae (Asian tree squirrels) Genus Callosciurus (Oriental tree squirrels, introduced into Europe and South America) Genus Exilisciurus (Asian pygmy squirrels) Genus Funambulus (Asian palm squirrels, introduced into Australia in the 1920s) Genus Glyphotes (sculptor squirrel) Genus Nannosciurus (Asian dwarf squirrel) Genus Prosciurillus (Sulawesi dwarf squirrels) Genus Rubrisciurus (Sulawesi giant squirrel) Genus Sundasciurus (Sunda squirrels) Genus Tamiops (Asian striped squirrels) Subfamily Xerinae Tribe Protoxerini (African tree squirrels) Genus Epixerus (African palm squirrels) Genus Funisciurus (rope squirrels) Genus Heliosciurus (sun squirrels) Genus Myosciurus (African pygmy squirrel) Genus Paraxerus (bush squirrels) Genus Protoxerus (African giant squirrels)
Relationship with humans
Squirrels are generally inquisitive and persistent animals. In residential neighborhoods, they are notorious for circumventing obstacles in order to eat from bird feeders. Although they are expert climbers, and primarily arboreal, some species of squirrels also thrive in urban environments, where they have adapted to humans.
As pets
Squirrels have been kept as pets in Western society at least until the 19th century. Because of their small size and tame nature, they were especially popular with women and the clergy.Kathleen Walker-Meikle, Medieval Pets, Woodbridge: The Boydell Press, 2012, p. 14 et passim
As pests
Squirrels are sometimes considered pests because of their propensity to chew on various edible and inedible objects, and their stubborn persistence in trying to get what they want. Their characteristic gnawing trait also aids in maintaining sharp teeth, and because their teeth grow continuously, prevents their over-growth. On occasion, squirrels will chew through plastic and even metal to get to the food.
Tree squirrels may bury food in the ground for later retrieval. Squirrels use their keen sense of smell to search for buried food, but can dig numerous holes in the process. This may become an annoyance to gardeners with strict landscape requirements, especially when the garden contains edibles.
Homeowners in areas with a heavy squirrel population must be vigilant in keeping attics, basements, and sheds carefully sealed to prevent property damage caused by nesting squirrels. A squirrel nest is called a "drey".
Squirrels can create serious fire hazards when they break into buildings. They often treat exposed power cables as tree branches, and gnaw on the electrical insulation. The resulting exposed conductors can short out, causing a fire. For this reason alone, squirrel nests inside buildings cannot be safely ignored. A squirrel nest will also cause problems with noise, excreta, unpleasant odors, and eventual structural damage.
Some homeowners resort to more interesting ways of dealing with this problem, such as collecting and placing fur from pets such as domestic cats and dogs in attics. It is thought that this fur would indicate to nesting squirrels that a potential predator roams, and will encourage evacuation. Odoriferous repellents, including mothballs and ammonia, are generally ineffective in expelling squirrels from buildings.
Once established in a nest, squirrels ignore fake owls and scarecrows, along with bright flashing lights, loud noises, and ultrasonic or electromagnetic devices. However, squirrels must leave the nest to obtain food and water (usually daily, except in bad weather), affording an opportunity to trap them or exclude them from re-entering.
To discourage chewing on an object, it can be coated or covered with something to make it distasteful: for instance a soft cloth doused with chili pepper paste or powder. Capsaicin and Ro-pel are other forms of repellent. To remain effective, the coating must be reapplied regularly, especially if it is exposed to the weather. Poisoning squirrels can be problematic because of the risks to other animals in the building, and because the odor of a dead squirrel in an attic or wall cavity is very unpleasant and persistent.
Trapping is often used to remove squirrels from residential structures. Effective baits include fruit, peanut butter, nuts, seeds and vanilla extract.
An alternative method is to wait until squirrels have left in search of food, and then close up all their access openings, or to install one-way trap doors or a carefully angled pipe. Attempting to get rid of all squirrels in a neighborhood is generally futile; the focus instead should be on physically excluding them from places where they can do damage. There are other humane techniques to remove squirrels from buildings, but removal is ineffective unless steps are taken to prevent them from immediately re-entering.
Squirrels are often the cause of power outages. They can readily climb a power pole and crawl or run along a power cable. The animals will climb onto power transformers or capacitors looking for food, or a place to cache acorns. If they touch a high voltage conductor and a grounded portion of the enclosure at the same time, they are electrocuted, and often cause a short circuit that shuts down equipment. Squirrels have brought down the NASDAQ stock market twice and were responsible for a spate of power outages at the University of Alabama. To sharpen their teeth, squirrels will often chew on tree branches or even the occasional live power line. Rubber or plastic plates, or freely rotating sleeves ("squirrel guards") are sometimes used to discourage access to these facilities.
Squirrels otherwise appear to be safe and pose almost zero risk of transmitting rabies.
Squirrels cause economic losses to homeowners, nut growers, and forest managers in addition to damage to electric transmission lines. These losses include direct damage to property, repairs, lost revenue and public relations. While dollar costs of these losses are sometimes calculated for isolated incidents, there is no tracking system to determine the total extent of the losses.
As roadkill and traffic hazards
In regions where squirrels are plentiful, roadkill is a common sight on roadways, especially in the spring and fall, when there is a fresh crop of young rodents. Motorists have caused serious accidents by attempting to swerve or stop to avoid a squirrel in the road. Evasive maneuvers are difficult since squirrels are much more agile and have much quicker reaction times than motorists in heavy vehicles; the majority of vehicular encounters end with no harm to either party.
An effort to mitigate these hazards to both squirrels and humans is the Nutty Narrows Bridge in Longview, Washington, listed on the National Register of Historic Places. It provides a way for squirrels to cross a busy street safely.
As urban wildlife Tree squirrels are a common type of urban wildlife. They can be trained to be hand-fed, and will take as much food as is available because they cache the surplus. Squirrels living in parks and campuses in cities have learned that humans are typically a ready source of food, either deliberately or from careless disposal of surplus. Some people do "squirrel fishing" as a way of simultaneously playing with and feeding squirrels.
Humans commonly offer various nuts and seeds; however, wildlife rehabilitators in the field have noted that neither raw nor roasted peanuts nor sunflower seeds are healthy for squirrels, because they are deficient in several essential nutrients. This type of deficiency has been found to cause metabolic bone disease, a somewhat common ailment found in malnourished squirrels.
As game
Squirrels are sometimes hunted as game animals, whether for their fur or as food. In the Middle Ages the red squirrel was hunted for its blue-gray winter coat, traditionally called vair, which now lends its name to a heraldic fur. The hairs from squirrel tails are prized in fly fishing when tying fishing flies.
In the US In many areas of the US, squirrels are still hunted for food, as they were historically.It tasted like chicken. Retrieved December 19, 2008. Recipes calling for squirrel even appear in cookbooks, including James Beard's American Cookery and pre-1997 copies of The Joy of Cooking. Squirrel meat can be substituted for rabbit or chicken in many recipes and was an ingredient in the original recipe for Brunswick stew, a popular dish in various parts of the Southern US. Other similar stews were also based on squirrel meat, often alongside other small game such as wild rabbit, including burgoo and Southern Illinois chowder.
Although squirrel meat is low in fat content, unlike most game meat it has been found by the American Heart Association to be high in cholesterol.
Squirrels Unlimited host a World Championship Squirrel cook-off each year in Bentonville, Arkansas.
In the UK For most of the history of the United Kingdom, squirrel has been a meat not commonly eaten, and even scorned by many. In the early 21st century however, the wild squirrel has become a more popular meat to cook with, showing up in restaurants and shops more often in Britain as a fashionable alternative meat. Specifically, Britons are cooking with the invasive grey squirrel, which is praised for its low fat content and the fact that it comes from free range sources. Additionally, the novelty of a meat considered unusual or special has contributed to the spread of squirrel consumption. Due to the difficulty of a clean kill and other factors, the majority of squirrel eaten in the UK is acquired from professional hunters, trappers and gamekeepers.
Some Britons are eating grey squirrel as a direct attempt to help the native red squirrel, which has been dwindling since the 19th-century introduction of the grey squirrel, resulting in dramatic habitat loss for the indigenous red squirrels. This factor was marketed by a national "Save Our Squirrels" campaign that used the slogan, "Save a red, eat a grey!"
Risks of eating