Ants are social insects that live in colonies being some of the most successful of insects. Ant colonies include one or more queens, workers, eggs, larvae and pupae. The worker ants maintain their developed structures known as "nests". Nests protect the ants against their enemies, some protection against extremes of weather, and are often placed close to water and food sources. Some ant species nest in the ground, many times under concrete or slabs. Some species will be found in wood such as fence posts, dead logs, and hollow trees or within structures. Ants are formed with a head, a thorax, or mid-section, and an abdomen connected to the thorax by a very short, narrow stalk. On their heads are mouths and mouthparts which are used to carry food or for defense. They have two compound eyes that are used to detect movement, and several single eyes, which are for the purpose of detecting light. Ants have two stomachs. They have a single stomach and a crop stomach. The single stomach is used to store food for the ant to digest. The crop stomach is more interesting; it contains food that the ant serves to the rest of the colony in times of need. In the event an ant is starving, it walks up to another ant and signs with its antennae "I'm hungry. Give me some food". The ant receiving the sign regurgitates some food for the starving ant to eat. Yum. Some ants also have stingers for defense purposes, or, on rare occasions, there is some which can spray a poison from the end of their abdomens. Ants can grow from point-zero-eight inches to an astounding two inches.