Wetas are living fossils, showing little or no change in body shape for millions of years.

Physical description
A stout, flightless cricket, brown in colour. They have large heads. The males have long, curved tusks that project forward from the jaws. They use these tusks to butt and push away rivals. Like other crickets, tusked wetas have powerful back legs. Some can jump up to 1 metre.

Distribution
The Middle Island tusked weta is native to Middle Mercury Island, off the coast of New Zealand. Because it is so endangered, conservationists began a captive breeding programme and have now established two new populations on nearby islands - Double Island and Red Mercury Island.

Habitat
They occupy a variety of habitats including forests and shrubland. They prefer damp conditions to dry conditions.

Diet
They are omnivorous, eating earthworms and beetles as well as fungi and plant material.

Behaviour
They are nocturnal. Unlike their tree-climbing relatives, Middle Island tusked wetas prefer to live on the ground, living in shallow scrapes in the soil that are covered with leaves.

Reproduction
The female pushes her ovipositor into the earth to lay her eggs under the soil.

Conservation status
The Middle Island tusked weta is the most endangered of the wetas and is protected.

Notes
In the absence of mammals, wetas have evolved to fill the place in a forest ecosystem usually taken by mice and voles.