|Eastern Gray Squirrel, Sciurus carolinensis|
Most squirrels are omnivores; they eat anything they find. Many kinds of squirrels live in trees, so they often find nuts. Despite living in trees squirrels are considered flightless because they can only jump short distances. They eat seeds, berries and pine cones too. Sometimes they eat bird's eggs and insects. Most tree squirrels store food in the fall, to eat in the winter. Ground squirrels do not store food. They hibernate which means they spend winter in a deep sleep.
Squirrels are indigenous to the Americas, Eurasia, and Africa, and have been introduced to Australia. The earliest known squirrels date from the Eocene and are most closely related to the mountain beaver and to the dormouse among living rodent families.
The most common European squirrels are red or brown in color, while common American squirrels are grey or black. Grey squirrels have been introduced into Europe (most notably, Great Britain), where they cause problems to the red squirrel's population. Red squirrels are protected in most of Europe. Squirrels have many predators or enemies. Foxes, raccoons, hawks and owls eat squirrels.
Squirrels breed in February and March in winter, and in June and July in summer. Females may become pregnant up to twice a year. Usually 4-6 young are born, after a gestation period (pregnancy) of around 39 days. Only the mother looks after the young, which are born completely helpless. Young squirrels are deaf and blind during the first few weeks of their life.
Most squirrels die in the first year of life. Adult squirrels can have a lifespan of 5 to 10 years in the wild. Some can survive 10 to 20 years in captivity.