Anthills are created as a by-product of worker ants digging subterranean tunnels. In fact, ants in general move more earth (soil) than any other organism, including earthworms. As the worker ants dig out the colony's tunnels, they dispose of the displaced earth by carrying it back out of the colony and depositing it near the entrance. They also dispose of any garbage found in the colony in this way. They carry these tiny bits of dirt and garbage in their mandibles. Usually, this combination of materials is dropped off at the top of the anthill, so it does not slide back down the hole into the colony, although some species of ants work to cultivate a specific shape to their anthills.