Ants are close relatives of bees and wasps and are can by identified by their three distinct body regions: head, thorax and abdomen, as well as antennae.
There are three kinds of ants in a colony: The queen (or queens), the female workers, and males. Ant communities are headed by a queen whose function in life is to lay thousands of eggs that will ensure the survival of the colony. Depending on the species, a colony may have one queen or many queens. Workers (the ants typically seen by humans) are wingless females that never reproduce, but instead forage for food, care for the queen's offspring, work on the nest, protect the community, and perform many other duties. Male ants often have only one role—mating with the queen soon after which they may die.
There is the common myth that seeing one ant indoors does not equal a full-blown infestation. Although this can be true, ants cooperate by leaving an invisible chemical trail for other ants to follow once they locate a promising food source. If that food source is in your home, you can count on ant colonies developing.