Ants vary in length from about 1/16 inch (1.6 mm) to nearly 2 inches (5 cm). Most species are red, black, brown, or yellow, and some are green or metallic blue. Ants, like other insects, have six legs. Their bodies are divided into three distinct segments: head, thorax, and abdomen. Unlike other insects, ants have elbowed (rather than straight or curved) antennae (feelers), and a pedicel, a narrow waistlike indentation between the thorax and abdomen. The crop, an organ located in the abdomen, is used to store food, which can later be regurgitated to feed other members of the colony.
Most ants are smooth-bodied, although some have spiny projections. Ants have strong jaws called mandibles, which are adapted for killing, crushing, chewing, cutting, or tearing, depending on the species and what it eats. Some species of ants have glands that produce formic acid, a strong acid that can be squirted on enemies, causing a burn or sting. Many ants have stingers that contain poison, and some, such as the harvester ants and fire ants, can inflict painful and, occasionally, fatal stings on humans and other animals.
Ants have tiny waists so they can wriggle their end parts freely! An ant’s waist has one or two movable parts. These parts allow the ant to twist and turn in different ways—an important feature for moving about an ant colony.
Ants have three main body parts: the head, the trunk, and the metasoma (meht uh SOH muh). The ant’s eyes, antennae, and mandibles (MAN duh buhlz) are located on its head.
Attached to the trunk are six legs with segments. Each leg has two claws at the foot. The claws hook into dirt, tree bark, or leaves, so ants can quickly walk, climb, and dig! Ants are strong, too. Many ants can lift 50 times their body weight!
The metasoma has two parts. They are the waist and the gaster. Organs for digesting, getting rid of waste, and reproducing are in the gaster. Some ant species have a sting at the end of the gaster to defend against other insects.
There are about 10,000 species of ants. So it is not surprising that ants, like millions of other social insects, live everywhere on land, except where it is really cold. In fact, areas with warm and moist climates have the most types of ants and other insects.
Tropical rain forests are very rich in insect life. If all the animals in the Amazon rain forest were weighed, many scientists think ants and termites would make up one-third of that weight.
Ants are successful survivors. They have different ways of life that allow them to live in different habitats. And their small size makes it easy for them to find food and shelter.
The ant's most highly developed sense is that of smell. Ants have abdominal glands that secrete a variety of pheromones, chemical substances that cause specific reactions by other individuals. Pheromones act as alarms, sex attractants, and trail markers; and they help individuals recognize each other. Ants have a well-developed sense of taste, and can distinguish sour, sweet, bitter, and salty tastes. Their sense of touch is keen. Touch, or tactile, receptors are located on the feet and on hairs on the legs. The antennae are used for smelling, tasting, and touching.
Some species of ants have compound eyes and well-developed vision, while others have simple eyes that can only distinguish between light and dark. Some species of ants are blind.