There are over 200 squirrel species living all over the world and they are all mammals. Squirrels, like all other mammals, have hair and mammary glands and give birth to live young.
Squirrels can be found on every continent except for Australia and are a part of the rodent family. They have four front teeth that never stop growing and they survive on a diet of nuts, leaves, roots, seeds and small insects. Their specific diet varies by species, but all squirrels are omnivores. There are three main kinds of squirrels: ground, tree and flying. They can live in either tree nests or underground burrows.