Tree squirrel

Eastern gray squirrel (Sciurus carolinensis)

Tree squirrels include over a hundred species found on all continents except Antarctica and are the members of the squirrel family most commonly referred to as "squirrels". They do not form a single natural, or monophyletic, group, but instead are related to the various other animals in the squirrel family, including ground squirrels, flying squirrels, marmots, and chipmunks. The most well-known genus is Sciurus, which includes the eastern gray squirrel of North America, introduced to Great Britain, the red squirrel of Eurasia, and the fox squirrel, among many others.

Classification

Indian palm squirrel (Funambulus palmarum)

The following genera within the squirrel family are classified as tree squirrels:

• Subfamily Ratufinae: Ratufa (Asian giant squirrels)
• Subfamily Sciurillinae: Sciurillus (South American pygmy squirrel)
• Subfamily Callosciurinae (Asian tree squirrels): Callosciurus (Oriental tree squirrels, introduced into Australia, Europe, and South America), Exilisciurus (Asian pygmy squirrels), Funambulus (Asian palm squirrels), Glyphotes (sculptor squirrel), Nannosciurus (Asian dwarf squirrel), Prosciurillus (Sulawesi dwarf squirrels), Rubrisciurus (Sulawesi giant squirrel), Sundasciurus (Sunda squirrels), Tamiops (Asian striped squirrels)
• Subfamily Xerinae
  • [Tribe Xerini (Afro-Eurasian ground squirrels)]
  • Tribe Protoxerini (African tree squirrels): Epixerus (African palm squirrels), Funisciurus (rope squirrels), Heliosciurus (sun squirrels), Myosciurus (African pygmy squirrel), Paraxerus (bush squirrels), Protoxerus (African giant squirrels)
  • [Tribe Marmotini (Eurasian and North American ground squirrels; marmots; chipmunks; prairie dogs)]
• Subfamily Sciurinae
  • [Tribe Pteromyini (flying squirrels)]
  • Tribe Sciurini (mostly American tree squirrels): Microsciurus (American dwarf squirrels), Rheithrosciurus (Borneo tufted ground squirrel), Sciurus (American and Eurasian tree squirrels), Syntheosciurus (Central American mountain squirrel), Tamiasciurus (American red squirrels)

Relationship with humans

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Eleanor Roosevelt in squirrel fur coat

Squirrels are generally clever and persistent animals. In residential neighborhoods, they are notorious for eating out of bird feeders, digging in planting pots and flower beds to pull out bulbs which they chew on or to either bury or recover seeds and nuts and for inhabiting sheltered areas including attics and basements. Squirrels use their keen sense of smell to locate buried nuts and can dig extensive holes in the process. Birds, especially crows, often watch a squirrel bury a nut, then dig it up as soon as the squirrel leaves. Although expert climbers, and primarily arboreal, squirrels also thrive in urban environments, where they get used to humans. Their intelligence makes them suitable as pets.

As pests

Squirrels are sometimes considered pests because of their propensity to chew on various edible and inedible objects. This characteristic trait aids in maintaining sharp teeth, and because their teeth grow continuously, prevents over-growth. Homeowners in areas with a heavy squirrel population must keep attics and basements carefully sealed to prevent property damage caused by nesting squirrels. A squirrel nest is called a "drey". Some homeowners resort to more interesting ways of dealing with this problem, such as collecting and planting fur from pets such as domestic cats and dogs in attics. This fur will indicate to nesting squirrels that a potential predator roams and will encourage evacuation. Fake owls and scarecrows are generally ignored by the animals, and the best way to prevent chewing on an object is to coat it with something to make it undesirable: for instance a soft cloth or chili pepper paste or powder. Squirrel trapping is also practised to remove them from residential areas. However, otherwise squirrels are safe neighbors that pose almost zero risk of transmitting rabies.

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This iron bird feeder is advertised as being "squirrel proof and bear resistant"

Squirrels are often the cause of power outages. They can readily climb a power pole and crawl across a power line. The animals will climb onto transformers or capacitors looking for food. If they touch a high voltage conductor and a grounded portion of the device at the same time, they are then electrocuted and cause a short circuit that shuts down equipment. Squirrels have brought down the high-tech NASDAQ stock market twice and were responsible for a spate of power outages at the University of Alabama. To sharpen their teeth they will often chew on tree branches or even the occasional live power line. Rubber plates (squirrel guards) are sometimes used to prevent access to these facilities.

Squirrels are blamed for economic losses to homeowners, nut growers, 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.

Squirrels are also responsible for burrowing into sensitive earthworks such as dams and levees, causing a loss of structural integrity which requires diligent maintenance and prevention. Squirrel burrowing activity has sometimes resulted in catastrophic failures of these structures.

As pets

Squirrels can be trained to be hand-fed. Because they are able to cache surplus food, they take as much food as is available. Squirrels living in parks and campuses in cities have learned that humans are typically a ready source of food. Urban squirrels have learned to get a lot of food from generous humans. A commonly given food is peanuts, but recent studies show that raw peanuts contain a trypsin inhibitor that prevents the absorption of protein in the intestines. Therefore offering peanuts that have been roasted is the better option. 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.

Squirrels are occasionally kept as household pets, provided they are selected young enough and are hand raised in a proper fashion. They can be taught to do tricks, and are said to be as intelligent as dogs in their ability to learn behaviors. Pet squirrels are usually kept without cages, but a large cage and a balanced diet with good variety will keep a pet squirrel healthy and happy. The pet owner must beware of "spring fever" at which time a female pet squirrel will become very defensive of her cage, considering it her nest, and will become somewhat aggressive to defend the area.

As food

Squirrel meat is considered a favored meat in certain regions of the United States where it can be listed as wild game. This is evidenced by extensive recipes for its preparation found in cookbooks, including older copies of The Joy of Cooking. Squirrel meat can be exchanged for rabbit or chicken in recipes, though it can have a gamey taste. Unlike the most game meat, the American Heart Association has found squirrel to be high in cholesterol.

In the U.S.

In many areas of the U.S., particularly areas of the American South, squirrels are hunted for food. Republican Presidential candidate Mike Huckabee mentioned his experiences eating squirrel during the South Carolina primary, saying that "When I was in college, we used to take a popcorn popper, because that was the only thing they would let us use in the dorm, and we would fry squirrels in a popcorn popper in the dorm room." He later told Meet the Press anchor Tim Russert that squirrel constitutes "a Southern delicacy". The Ramapough Mountain Indian Tribe of New Jesery considered eating squirrel to be a tradition.

In the U.K.

For most of the history of the United Kingdom, squirrel has been a meat not commonly eaten, and even scorned by many.

But in the early 21st century, 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, U.K. citizens are cooking with the invasive gray squirrel, which is being 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 added to the spread of squirrel consumption. Due to the difficulty of a clean kill and other factors, the majority of squirrel eaten in the U.K. is acquired from professional hunters, trappers, and gamekeepers.

Some Britons are eating the gray squirrel as a direct attempt to help the native red squirrel, which has been dwindling since the introduction of the gray squirrel in the 19th century. This factor was marketed by a national "Save Our Squirrels" campaign that used the slogan, “Save a red, eat a gray!”

In culture

Despite periodic complaints about the animal as a pest, general public opinion towards the animal is favorable, thanks to its agreeable appearance, intelligence and its eating styles and habits. Squirrels are popular characters in many forms of media, such as the literary works of Beatrix Potter, Brian Jacques' Redwall series (including Jess Squirrel and numerous other squirrels), Pattertwig in C. S. Lewis' Prince Caspian, Michael Tod's Woodstock Saga of novels featuring squirrel communities in the style of Watership Down, and the Starwife and her subjects from Robin Jarvis's Deptford novels. Squirrels are also popular characters in cartoons, such as Scrat from Ice Age, Slappy Squirrel of the Animaniacs, Sandy Cheeks from SpongeBob SquarePants, Hammy from Over the Hedge, Benny in The Wild, Rodney and Leon and Darlene from Squirrel Boy, Secret Squirrel, Screwy Squirrel, Nutty from Happy Tree Friends, and Rocky, Bullwinkle's adventuring partner. Grace from the webcomic El Goonish Shive is often pictured as an anthropomorphic squirrel, since it is her most natural and favored form. Video games such as Rare's Conker series starring Conker the Squirrel, as well as Ocean Software's Mr. Nutz. There is even a squirrel-themed super-heroine, Squirrel Girl.

Albino and white squirrels

Further information: Albinism § Albinism and related conditions in animals

Further information: Leucism

One of the ways that squirrels impact human society is inspired by the fascination that people seem to have over local populations of white squirrels (often mis-identified as being albino). This manifests itself by the creation of social group communities that form from a commonly-shared interest in these rare animals. These groups demonstrate classic sociological group dynamics, including personal identity by belonging to a group, as well as hierarchical competition between white squirrel groups with each other over which has the best local white squirrel population. Other impacts on human society inspired by white squirrels include the creation of organizations that seek to protect them from human predation, and the use of the white squirrel image as a cultural icon.

Welcome sign for Kenton, Tennessee, an example of competition for "White Squirrel Capital".

Some examples of this cultural impact include:

• Olney, Illinois, known as the "White Squirrel Capital of the World," is home of the world's largest known white squirrel colony. These squirrels have the right of way on all streets in the town, with a $500 fine for hitting one. The Olney Police Department features the image of a white squirrel on its officers' uniform patches.
• Along with Olney, there are four other towns in North America that avidly compete with each other to be the official "Home of the White Squirrel", namely: Marionville, Missouri, Brevard, North Carolina, Exeter, Ontario, and Kenton, Tennessee, each of which holds an annual white squirrel festival, among other things designed to promote their claim of "White Squirrel Capital".
• Other towns that have reported white squirrel populations in North America (although not necessarily at war with other towns to be the "official" white squirrel capital) include Dayton, Ohio, DeForest, Wisconsin, and some of the snowbelt cities in the Western, Central and Finger Lakes regions of New York state (Buffalo, Rochester, and Syracuse).

In addition to the various towns that boast of their white squirrel populations, there also is a surprisingly large number of university campuses in North America that have white squirrels, including:

• The University of Texas at Austin, which has an Albino Squirrel Preservation Society, founded 2001, along with its sister chapter at University of North Texas. In 2006, the University of Texas at Austin held a student referendum to name their white squirrel as the university's secondary mascot, however the vote was narrowly defeated by the student body.
• Michigan Technological University in Houghton, Michigan is home to frequently-sighted white squirrels that live on and around the campus. A Facebook group dedicated to these squirrels, called I've Seen the Albino Squirrel of Michigan Tech, was created for people to post photographs and anecdotes of their encounters with the white squirrels, and includes some stories from Michigan Tech alumni that recall seeing white squirrels in Houghton dating back to the 1930s.
• The University of Louisville in Kentucky has established its own chapter of "The Albino Squirrel Preservation Society", which maintains contact with its members and interested parties through a Facebook group by that name. The university has an open policy to give away a free t-shirt to anyone who brings a photograph to the administration offices that was taken of an albino squirrel on campus grounds.
• Other university campuses that have albino squirrel populations include Ohio State University in Columbus, Ohio, Western Kentucky University in Bowling Green, Kentucky (which has had a population of albino squirrels since the 1960s), and Youngstown State University in Youngstown, Ohio.

An true albino squirrel. Note the pink eyes.

A white squirrel. Note the non-pink eyes.

Although these squirrels are commonly refered to as albinos, most of them are likely non-albino squirrels that exhibit a rare white fur coloration known as leucism that is as a result of a recessive gene found within certain Eastern gray squirrel (Sciurus carolinensis) populations, and so technically they ought to be refered to as white squirrels, instead of albino. Dr. Michael Stokes, a biology professor at Western Kentucky University, commented that the probable cause for the abundance of white squirrels on university campuses was due to them being originally introduced by someone:

"We’re not sure how they got here, but I’ll tell you how it usually happens...When you see them, especially around a college campus or parks, somebody brought them in because they thought it would be neat to have white squirrels around."

Dr. Albert Meier, another biology professor at Western Kentucky University, added that:

"...white squirrels rarely survive in the wild because they can’t easily hide. But on a college campus, they are less likely to be consumed by other animals."

A list of white squirrel sightings around the world is maintained by the White Squirrel Research Institute, a group based in Brevard, North Carolina.

Red squirrel at feeding tray in the lake district.

Red and grey squirrels in the UK

A decline of the red squirrel and the rise of the eastern grey squirrel has been widely remarked upon in British popular culture. It is mostly regarded as the invading greys driving out the native red species. Evidence also shows that grey squirrels are vectors of the Squirrel parapoxvirus for which no vaccine is presently available and which is deadly to red squirrels but does not seem to affect the host. Currently the red squirrel only resides in a few isolated areas of the UK, notably in Scotland, and in England Formby, the Lake District, Brownsea Island, and the Isle of Wight. Special measures are in place to contain and remove any infiltration of grey squirrels into these areas.

Under British law, the eastern grey squirrel is regarded as vermin, and at one point it was illegal to release any into the wild; any caught had to be either destroyed or kept captive. In 2008 the law was altered, allowing those with the proper license to release captured grey squirrels.

Literature cited

• Andrew Duff and Ann Lawson (2004). Mammals of the World: A checklist. A & C Black. ISBN 071366021X.
• Musser, G. 2010. squirrel. In Encyclopædia Britannica. Retrieved February 19, 2010.
• Nowak, Ronald M. 1999. Walker's Mammals of the World, 6th edition. Johns Hopkins University Press, 1936 pp. ISBN 0-8018-5789-9
• Thorington, R.W., Jr. and Hoffmann, R.S. 2005. Family Sciuridae. Pp. 754-818 in Wilson, D.E. and Reeder, D.M. (eds.). Mammal Species of the World: a taxonomic and geographic reference. 3rd ed. Baltimore: The Johns Hopkins University Press, 2 vols., 2142 pp. ISBN 0-8018-8221-4