Tree squirrel
Arboreal rodents found worldwide except Antarctica and Oceania.
Tree squirrels are the animals most people mean when they say "squirrel." They belong to the squirrel family, Sciuridae, and include over 100 species that live in trees. These species are found on every continent except Antarctica and Oceania. However, tree squirrels are not a single, closely related group. Instead, they are connected in various ways to other members of the squirrel family, such as ground squirrels, flying squirrels, marmots, and chipmunks. What defines a tree squirrel is its habitat, not its body structure. Unlike squirrels that dig burrows in the ground or among rocks, tree squirrels spend most of their lives in trees. One exception is the flying squirrel, which also lives in trees but has a physical difference: special skin flaps called patagia that let it glide.
The most well-known group of tree squirrels is the genus *Sciurus*. This includes the eastern gray squirrel (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, including farms, suburban backyards, and city parks.
**Classification**
Current taxonomy, based on genetic data, splits tree squirrels into several subfamilies. The following genera are classified as tree squirrels:
- **Subfamily Ratufinae:** *Ratufa* (Asian giant squirrels) - **Subfamily Sciurillinae:** *Sciurillus* (South American pygmy squirrel) - **Subfamily Sciurinae:** Tribe Sciurini (mostly American tree squirrels): *Microsciurus* (American dwarf squirrels), *Rheithrosciurus* (Borneo tufted ground squirrel), *Sciurus* (Eurasian and American tree squirrels), *Syntheosciurus* (Central American mountain squirrel), *Tamiasciurus* (American pine squirrels) - **Subfamily Callosciurinae** (Asian tree squirrels): *Callosciurus* (Oriental tree squirrels, introduced into Europe and South America), *Exilisciurus* (Asian pygmy squirrels), *Funambulus* (Asian palm squirrels, introduced into Australia in the 1920s), *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 Protoxerini (African tree squirrels): *Epixerus* (African palm squirrels), *Funisciurus* (rope squirrels), *Heli
- classification
- Family Sciuridae, multiple subfamilies
- defining_characteristic
- Arboreal habitat, not physiology
- best_known_genus
- Sciurus
- native_range
- All continents except Antarctica and Oceania
- number_of_species
- More than 100
- notable_exception
- Flying squirrels (have patagia for gliding)
Lore & Background
Tree squirrels are a diverse group within the squirrel family, defined by their tree-dwelling habitat rather than by a single evolutionary lineage. The best-known genus 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. Many tree squirrel species have adapted to human-altered environments such as rural farms, suburban backyards, and urban parks.
Current taxonomy, based on genetic data, splits tree squirrels into several subfamilies: Ratufinae (Asian giant squirrels), Sciurillinae (South American pygmy squirrel), Sciurinae (mostly American tree squirrels), Callosciurinae (Asian tree squirrels), and Xerinae (African tree squirrels). These subfamilies include numerous genera, such as Microsciurus, Tamiasciurus, Callosciurus, Funambulus, and Protoxerus.
Tree squirrels are generally inquisitive and persistent animals. In residential neighborhoods, they are notorious for circumventing obstacles to eat from bird feeders. They have been kept as pets in Western society at least until the 19th century, especially popular with women and the clergy due to their small size and tame nature.
Reader's Guide
Tree squirrels are significant as a widespread and adaptable group of rodents that interact extensively with human environments. They are considered pests because of their propensity to chew on various objects, including electrical insulation, which can cause fires and power outages. They have brought down the NASDAQ stock market twice and caused power outages at the University of Alabama. Their gnawing maintains sharp teeth and prevents overgrowth. Squirrels bury food for later retrieval, using their keen sense of smell, which can annoy gardeners. Homeowners must seal attics and basements to prevent nesting, as squirrel nests (called dreys) can cause noise, excreta, odors, and structural damage. Repellents such as capsaicin and Ro-pel are used, but trapping with baits like peanut butter and nuts is common. Squirrels pose almost zero risk of transmitting rabies. They are also a common sight as roadkill, especially in spring and fall, and motorist evasive maneuvers can cause accidents. The Nutty Narrows Bridge in Longview, Washington, provides a safe crossing for squirrels. Tree squirrels are a common type of urban wildlife and can be trained to be hand-fed.
Did You Know?
- Tree squirrels do not form a single natural, or monophyletic, group.
- The defining characteristic of tree squirrels is their habitat, not their physiology.
- Squirrels have brought down the NASDAQ stock market twice.
- A squirrel nest is called a 'drey'.
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