Today, animals are used for pest control. They have been for thousands of years. Ancient Egyptians trained ferrets to catch mice. Cats then overthrew the ferrets. They still do today. Pigs were trained by Pilgrims to kill rattlesnakes. Today, ladybugs and worms are used in gardens and farms to get rid of aphids and weeds. And bats are used to rid farms of mosquitos, moths and other insects.