Discern whether an ant is a queen or worker by examining the ant's size, shape and wings. Queens are usually larger, have a complex thorax and have wings that are shed sometime during adulthood. Another way to discern a queen ant from a worker ant is by noting which ant reproduces. Queen ants are fertile females, while worker ants are non-fertile.
In most species, queen ants are the largest ones in the colony. Because queens are born with wings, they can fly out of their own colonies to mate with males elsewhere. The thorax, or middle part of the body, is larger on queens to support the wings. Queen ants can live up to 30 years while workers, on average, live for three.
Worker ants are usually smaller than queens and do more work in the colony. A queen's job is to mate and reproduce, while a worker's job is to take care of the nest, protect the colony against predators, and care for the queen and her young. Males ants' primary job is to mate with the queen.
Although most species of ants share this hierarchy, there are a few exceptions. Some colonies live with and serve a single queen, while others live with many queens. Some species also have winged males, which could make identifying the queen more difficult. Also, certain rare ant species have queens that are smaller than workers.