Ants are closely related to wasps and bees, and so share several important physical characteristics with them, including pronounced antennae, a narrow, hour-glass shaped waist and- with the exception of some wingless ant species- two pairs of transparent wings. Because they are hardy, reproduce well and eat a broad range of plant and animal foods, ants can (and do) live almost anywhere on the planet.   Ants are also very highly evolved, at least in comparison to the rest of the insect world. They live together in colonies, and possess a complex and extremely ordered social structure. Thus, while the size of a given colony may vary greatly from one species of ant to the next, its strict social hierarchy does not. A typical colony consists of: One or more large queens, who lay eggs and produce young A handful of smaller males, who exist for the sole purpose of mating with the queen Scores of sterile females, who account for the vast bulk of the colony's population and do nearly all of the work (procuring food, rearing the young, protecting the colony, etc.) This rigid social system may not be at all democratic, but it is highly effective in perpetuating the species. As a result, ants just might be the most numerous animal on Earth. If not, they are surely right near the top of the list.