25 Bulldog Ant Facts: Australia's Fierce Giant Ants

Bulldog ants, also called bull ants, belong to a group of ants called Myrmecia.

There are around 90 species of bulldog ant.

Almost all of them live only in Australia. Just one species is found outside the country, on the island of New Caledonia.

They are also known as inch ants, sergeant ants and, for some smaller jumping species, jack jumpers.

Bulldog ants are among the largest ants in the world, and some workers grow up to about 4 centimetres long.

They have long, toothed jaws called mandibles that they use to grab prey.

Many bulldog ants are black, red, orange or a mix of these colours, often with brightly coloured jaws.

Unlike most ants, bulldog ants have large eyes and excellent eyesight, and they can spot moving objects from about a metre away.

Bulldog ants hunt mainly by sight, tracking insects as they move.

One bulldog ant species has just a single chromosome

Most animals carry many chromosomes in their cells. Humans have 46. But in the bulldog ant species Myrmecia croslandi, males have just one chromosome and females have only two. This is the lowest number possible for any animal. Scientists have studied this tiny ant to learn more about how chromosomes and genes evolve.

Jack jumpers can leap several centimetres at a time, which makes them surprisingly hard to escape.

Unlike most ants, which follow scent trails in long lines, bulldog ant workers usually hunt alone.

Adult bulldog ants mainly drink sweet nectar and plant sap, while the insects they catch are fed to their growing larvae.

They build underground nests, often with a small mound of soil or gravel around the entrance.

A bulldog ant colony usually has a few hundred to a couple of thousand workers.

A new queen starts a colony by herself and goes out hunting for food until her first workers are ready to help.

Bulldog ants fiercely defend their nest and will chase and sting intruders, including people.

Their stinger isn't barbed, so a bulldog ant can sting again and again.

Some bulldog ants hunt at night. Scientists studying them have found they can navigate in near darkness using landmarks and patterns of light in the sky.

Jack jumper stings can be dangerous for some people

Jack jumpers are small bulldog ants that leap at intruders and deliver a painful sting. For most people, a sting causes intense pain, redness and swelling. But a small number of people are seriously allergic to jack jumper venom, and stings have caused deaths in Australia from severe allergic reactions. Tasmania, where jack jumpers are especially common, runs a special treatment programme that slowly trains allergic people's bodies to tolerate the venom.

Bulldog ant stings are extremely painful, but the bullet ant of South America is usually considered to have the most painful sting of any insect.

Bulldog ants belong to a very ancient group of ants, and are sometimes described as living fossils.

Like other ants, only the queens and males have wings, which they use during mating flights.

Bulldog ant queens can live for many years, keeping their colonies going.

The popular story that a bulldog ant cut in half will make its head and tail fight each other is a legend. Any movement is just a reflex, not a real fight.