Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels, chipmunks, marmots, flying squirrels, and prairie dogs amongst other rodents. Squirrels are indigenous to the Americas, Eurasia, and Africa, and were introduced by humans to Australia. Like other rodents, squirrels have four front teeth that never stop growing, so they don’t wear down from the constant gnawing. Tree squirrels are the types most commonly recognized, often seen gracefully scampering and leaping from branch to branch. Ground squirrels eat nuts, leaves, roots, seeds, and other plants. They also catch and eat small animals, such as insects and caterpillars. Tree squirrels are commonly seen everywhere, from woodlands to city parks. Though they are terrific climbers, these squirrels do come to the ground in search of fare such as nuts, acorns, berries, and flowers. They also eat bark, eggs, or baby birds.