Squirrels are familiar to almost everyone. More than 200 squirrel species live all over the world, with the notable exception of Australia. The tiniest squirrel is the aptly named African pygmy squirrel—only five inches (thirteen centimeters) long from nose to tail. Others reach sizes shocking to those who are only familiar with common tree squirrels. The Indian giant squirrel is three feet (almost a meter) long. Like other rodents, squirrels have four front teeth that never stop growing so they don’t wear down from the constant gnawing. Source: National Geographic