Tree squirrels include over a hundred species that are found on all continents except Antarctica, and are the members of the squirrel family (Sciuridae) 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 defining characteristic that is used to determine which of the various species of Sciuridae are tree squirrels is therefore not so dependent on their physiology, but their habitat. Tree squirrels live mostly among trees, as opposed to other squirrels that live in burrows in the ground or among rocks. However, there is one exception to this rule, as physiological distinction does make a difference in regard to flying squirrels, who also make their home in trees, but have unique physical characteristics that separate them from their tree squirrel cousins (specifically, special flaps of skin that act as glider wings, allowing them to "fly").
The most well known genus of tree squirrels is Sciurus, which includes the Eastern gray squirrel of North America (and which was introduced]when?[ to Great Britain]citation needed[), the red squirrel of Eurasia, and the North American fox squirrel, among many others. Since many tree squirrel species have readily adapted to human-altered environments (including intensely cultivated farms and urban cities), and because they are mostly diurnal (active during the daytime), when most people are outdoors to see them, they are perhaps the most familiar members of the rodent family to most humans. In some larger cities, they are often the only wild animals (not counting birds) that most people ever see.
Latin American culture is the formal or informal expression of the people of Latin America, and includes both high culture (literature, high art) and popular culture (music, folk art and dance) as well as religion and other customary practices.
Definitions of Latin America vary. From a cultural perspective,* Latin America generally includes those parts of the Americas where Spanish, French or Portuguese prevail: Mexico, most of Central America, and South America. There is also an important Latin American cultural presence in the United States (e.g. California and the Southwest, and cities such as New York and Miami). There is also increasing attention to the relations between Latin America and the Caribbean as a whole. See further discussion of definitions at Latin America.
The American red squirrel (Tamiasciurus hudsonicus) is one of three species of tree squirrel currently classified in the genus Tamiasciurus, known as the pine squirrels (the others are the Douglas squirrel, T. douglasii and Mearns's squirrel, T. mearnsi). American red squirrels are also referred to as pine squirrels, North American red squirrels, and chickarees. They are medium-sized (200–250 g) diurnal mammals that defend a year-round exclusive territory. The diet of these tree squirrels is specialized on the seeds of conifer cones. As such, they are widely distributed across North America wherever conifers are common, except on the Pacific coast, where they are replaced by Douglas squirrels. Recently, American red squirrels have been expanding their range to include primarily hardwood areas.
The Siberian flying squirrel (Pteromys volans) is an Old World flying squirrel with a range from the Baltic Sea in the west to the Pacific coast in the east. It is the only species of flying squirrel found in Europe. It is considered vulnerable within the European Union where it is found only in Finland, Estonia and Latvia.
A female Siberian flying squirrel weighs about 150 grams, the males being slightly smaller on average. The body is 13–20 cm long, with a 9–14 cm long flattened tail. The eyes are large and strikingly black. The coat is gray all over, the abdomen being slightly lighter than the back, with a black stripe between the neck and the forelimb. A distinctive feature of flying squirrels is the furry glide membrane or patagium, a flap of skin that stretches between the front and rear legs. By spreading this membrane the flying squirrel may glide from tree to tree across distances of over a hundred metres, and have been known to record a glide ratio of 3.31, but is normally 1-1.5.