Ants are social insects closely related to wasps and bees. Ants evolved from wasp-like ancestors between 110 and 130 million years ago. More than 12,500 out of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and a distinctive slender waist.
Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organized colonies which may consist of millions of individuals. These larger colonies consist mostly of sterile wingless females forming castes of workers, soldiers, or other specialized groups. Nearly all ant colonies also have some fertile males called drones and one or more fertile females called queens. The colonies are sometimes described as superorganisms because they appear to operate as a unified entity, collectively working together to support the colony.
Ants have colonized almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote islands in Greenland, Iceland and Hawaii. Ants thrive in most ecosystems, and may form up to 25% of the terrestrial animal biomass. Their success in so many environments has been attributed to their social organization and their ability to modify habitats, tap resources, and defend themselves.
Ant societies have organized jobs, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been a subject of study.
Many human cultures make use of ants in cuisine, medication and rituals. Some species are valued in their role as biological pest control agents. However, their ability to exploit resources brings them into conflict with humans. They can damage crops and invade our dwellings. Some species, such as the red imported fire ant, are regarded as invasive species, establishing themselves in areas where they are accidentally introduced. Fire ants can be deadly to humans and animals.