Ant

Ants (family Formicidae) are eusocial insects belonging to the order Hymenoptera, which also includes wasps and bees. They are easily identified by their elbowed antennae and the distinctive node-like structure that forms their slender waists.

Ants range in size from 0.75 to 52 mm, the largest species being the fossil Titanomyrma giganteum. Most ants are yellow, red, brown, or black, though a few species are green and some tropical species have a metallic sheen.

More than 13,800 species are currently known worldwide, and ants have colonised almost every landmass on Earth - the only exceptions being Antarctica and a handful of remote islands. They thrive in moist tropical ecosystems, and some species make use of the controlled micro-climate inside human dwellings to house their colonies.

Ants live in colonies that can range from a few dozen individuals in a small natural cavity to supercolonies of hundreds of millions. A typical colony contains sterile female workers, soldiers, fertile males called drones, and one or more fertile females called queens. Because each ant works as part of this collective, colonies are often described as superorganisms.

Ants evolved from vespoid wasp ancestors during the Cretaceous period, and the oldest ant fossils date to around 113-100 million years ago. In 1966 a fossil ant, Sphecomyrma, was found preserved in amber dating back around 92 million years, with features found in some wasps but not in modern ants.

Modern ant subfamilies began to appear towards the end of the Cretaceous, around 80-70 million years ago. Ants then diversified extensively during the Angiosperm Terrestrial Revolution and assumed ecological dominance around 60 million years ago. By the Oligocene and Miocene epochs, ants made up 20-40 per cent of all insects found in major fossil deposits.

During the Cretaceous, primitive ants ranged widely across the ancient northern supercontinent of Laurasia. Their success has been attributed to their remarkable social organisation, their ability to modify habitats, exploit resources, and defend themselves effectively - traits that have allowed them to spread to almost every corner of the planet over millions of years.

Ants are highly social insects whose colonies function almost like a single organism. Division of labour is central to colony life: workers forage, maintain the nest, and care for young, larger 'soldier' workers have stronger mandibles that make them more effective in fighting, and queens are the fertile females.

Communication is sophisticated. Ants use pheromones, touch, and sound to coordinate everything from foraging trails to alarm responses. A forager that finds food lays a scent trail back to the nest; others follow and reinforce it, and the trail fades naturally once the food is gone. A crushed ant releases an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from farther away.

Task roles can shift with age. Young workers typically care for the queen and larvae first, then move on to nest construction, and later to foraging and defence. In the ant Temnothorax albipennis, experienced foragers can lead naive nest-mates to food through tandem running, and ants may be the only group apart from mammals where interactive teaching has been observed.

Ants defend themselves by biting and, in many species, stinging or spraying chemicals such as formic acid. Secretions from special glands also have antibiotic properties that help protect the colony from pathogens. Workers actively maintain colony hygiene, including removing dead nest-mates.

Ant queens are remarkably long-lived for insects of their size, with lifespans of up to 30 years recorded. Workers live from one to three years, while males are much more short-lived, surviving for only a few weeks.

In cooler regions, ants survive winter by entering a state of reduced activity or hibernation. Some species have larvae that enter a dormant state called diapause, while in others only the adults reduce their activity until warmer weather returns.

Colony health depends heavily on maintaining the right conditions for the brood. Larvae and pupae need fairly constant temperatures for proper development, and workers move them between chambers within the nest to achieve this. The metapleural glands, unique to ants, produce chemicals with antibiotic properties that help protect the colony from infection.

This is general awareness only, not veterinary advice. If you find an injured or unwell wild animal, contact a vet or a wildlife rescue.

How long do ants live?

It depends on their role in the colony. Queens can live for up to 30 years, making them extraordinarily long-lived for insects - estimated to live around 100 times longer than solitary insects of a similar size. Workers live from one to three years, while male drones survive only a few weeks.

Do all ant nests have a queen?

Not necessarily. Some ant nests have multiple queens, while others may exist without a queen at all. In those colonies, certain workers called gamergates are capable of reproducing and keeping the colony going.

How do ants find their way back to the nest?

Ants use scent trails and visual landmarks to navigate, desert ants such as Cataglyphis use the position of the sun, and some species can even use the Earth's magnetic field. Foraging ants can travel up to 200 metres from their nest and still find their way back, even in the dark, by following pheromone trails left on the ground.

Can ants sting?

Many species can sting as well as bite. Workers in many species have egg-laying structures modified into stings used for defence. Some ants also spray or secrete chemicals such as formic acid. Some species have stings that can be dangerous, such as jack jumper ants, whose sting can be lethal for humans.

Do ants sleep or are they active all year?

In tropical regions ants are active all year round, but in cooler regions they survive winter in a state of hibernation or reduced activity. Some species have larvae that enter a dormant state, while in others the adults simply slow down until spring.

Is it true that ant colonies always have just one queen?

This is a common misconception. While some colonies have a single queen, others have multiple queens. Colony structure varies considerably between species, and in the red imported fire ant, differences in a single gene can decide whether a colony will have one queen or many.

The word ant comes from Old English and originally meant "the biter" - a very fitting name for an insect that defends itself so effectively with its jaws.

The total number of ants alive on Earth at any one time is estimated at around 20 quadrillion - that is 20 followed by 15 zeros. Their combined weight is greater than that of all wild birds and mammals put together.

Ant queens are estimated to live roughly 100 times longer than solitary insects of a similar size.

Some ant species are farmers. Leafcutter ants cultivate a specific fungus inside their nests, cutting leaves to feed the fungal gardens and then eating the structures the fungus produces. Symbiotic bacteria on the outside of their bodies produce antibiotics that kill bacteria brought into the nest that may harm the fungus.

Ants may be the only group of animals apart from mammals in which interactive teaching has been clearly observed - with experienced foragers actively guiding inexperienced nest-mates to food sources, slowing down or speeding up in response to the learner's progress.