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What is an insect?

The internal organs of an insectThe internal organs of an insectInsects are invertebrates, animals without backbones. They have six jointed legs and a hard external skeleton. All insects have three main body parts: the head, the thorax and the abdomen. The eyes, jaws and antennae (feelers) are found on the head. Both legs and wings are attached to the thorax. The abdomen contains the intestines. There are probably more than 10 million types of insect. They are divided into a number of major groups: ants, flies, bugs and so on.

The body parts of an insectThe body parts of an insect

A cricket, showing its legs and feetA cricket, showing its legs and feet


All insects have six legs, which are made up of several jointed sections. Tiny bristles on the legs and body can feel vibrations caused by sound or movement. Some insects, such as crickets, have ears on their legs. The end part of an insect’s leg, its foot, is called the tarsus. The claw is used for gripping surfaces.

The tiny flea can jump more than 100 times its own length. It feeds on the blood of larger animals, such as rats.

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