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Land invertebrates


A woodlouse or pill bug, curling up into a ball.A woodlouse or pill bug, curling up into a ball. Woodlice are small crustaceansarthropods with a hard, segmented exoskeleton, known as a cuticle, and two pairs of antennae. Woodlice have seven pairs of legs. They live in cool, damp places and eat dead vegetation. Some kinds of woodlouse, known as pill bugs, curl up into an almost perfectly spherical ball when they are threatened.


Woodlice rapidly lose water from their bodies, and so they are usually found in damp places where there is always moisture, such as under rocks and logs. Most species are nocturnal and feed on dead plant matter.

A woodlouse moultingA woodlouse moultingThe woodlouse must shed, or moult, its shell-like cuticle as it grows, which it does in two stages. The female woodlouse carries her eggs in a pouch on the underside of her body, until they hatch out into tiny babies.

Spiky yellow woodlouseSpiky yellow woodlouse

Spiky yellow

Woodlice are crustaceans, like crabs, so they breathe through gills—which is why they live only in damp conditions. Their gills are normally on their abdomens.

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