They are mottled black, white and gold. Each female will lay up to 100 eggs in spring and early summer on furs, wool and natural fibres. These eggs hatch into hairy, brown larvae, commonly known as woolly bears. The woolly bears avoid light and curl into a ball when approached. It is the larvae that cause damage to natural fibres, as they feed and grow.
A female beetle will usually lay around 20-100 eggs, and these usually take around 10-35 days to hatch depending on the temperature.
The larvae of a carpet beetle can grow to 4mm in length, moulting as it develops. They are usually covered in brown hairs and have a tendency to curl up in a ball when disturbed. They also have a tendency to shy away from the light, favouring the dark instead. In their larval form, carpet beetles feed on feathers, fur, hair, and wool and typically enter airing cupboards causing damage to clothing, blankets, and other textiles.