Ants are wondrous creatures and one of the most successful animals on earth. In nature, ants are a prime food source for many animals.They aerate more soil than the earthworm, they have taken advantage of every conceivable environmental niche and can be found in every region of the world except the polar caps. Ants are successful because they are social insects often forming complex colonies. Certain species of ants are specialized in their behavior, for example, living on only one type of tree. Many other species are very adaptable and exploit numerous different living environments and food sources. The presence of ants in nature ensures the health of the natural environment. In homes and other buildings, however, ants are not so welcome. The same reasons ants are successful in nature makes them very well suited to sharing man's living quarters. Structures can be threatened by damage from carpenter ants. Pharaoh ants can carry disease organisms. The stings of fire ants can threaten a person's health.