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Goat moth (Cossus cossus)

Bulky yet well-disguised, this goliath is the heaviest moth in the UK! Spot the adults when they emerge in mid-summer after feeding on the wood of broadleaf trees as larvae.

  • The goat moth is the heaviest moth in the UK.

    Credit: Andrew Darrington / Alamy Stock Photo

  • They overwinter as pupae.

    Credit: ARCO / naturepl.com

  • This species is very hard to spot as it is camouflaged to resemble cracked wood.

    Credit: ARCO / naturepl.com

Quick facts

Common name: goat moth

Scientific name: Cossus cossus

Family: Cossidae

Habitat: woodland, hedgerows, parks and gardens

Predators: birds, small mammals

Origin: native

What do goat moths look like?

Adults: the goat moth is a large moth. It has grey colouring with black and white markings which give it the appearance of cracked wood. It has a wingspan of up to 95mm.

Larvae: the larva is very large, growing up to 10cm long. It is dark red with lighter orangey sides and a black head.

What do goat moths eat?

Adults: these moths do not feed as adults. 

Larvae: eat the wood of deciduous trees. The waste and sap they produce while eating leaks out of their nest hole and attracts many other insect species, including the red admiral butterfly.

Credit: Robert Thompson / naturepl.com

How do goat moths breed?

Larvae burrow holes into broadleaved trees like oak or ash. They spend up to five years growing until they are ready to pupate. In August or September, larvae leave their burrow homes to pupate on the ground, wrapping themselves in a soil cocoon. They overwinter as pupae and emerge as adults in the summer.

Did you know?

The goat moth gets its name from the musky ‘goat-like’ smell of the caterpillar.

Where do goat moths live?

The goat moth is a nationally scarce species, only found in scattered locations in England.

Credit: ARCO / naturepl.com

Signs and spotting tips

Larvae can be seen in August when they leave their nesting area. Adults are on the wing in June and July. Look for them in woodland near oak and ash, but you’ll need a keen eye to spot them!

Threats and conservation

A loss of habitat and suitable host trees is the main threat to the goat moth. They are a listed priority species on the UK Biodiversity Action Plan.

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