Squirrels are considered one of the most active mammals in the world. These tiny creatures can run, jump and climb trees at extraordinary speeds. These little creatures have been observed to have few to no natural predators. Many homeowners use squirrels as a form of pest control in their homes, as they have been followed to kill off cockroaches, mice, voles, and other small rodents. Squirrels have also been observed to eat fruit and nuts and fungi, insects, and invertebrates.