How a reptile 'saws through prey'

New Zealand's tuatara has a unique way of chewing its food, say scientists who have studied its jaws in detail.

This beak-headed reptile uses a "steak knife sawing motion" as it chews.

This could help explain how the species has continued to adapt to a changing world - and changes in available prey - over more than 200 million years.

A computer model of the tuatara, recreating its jaws as it munched on prey, revealed that it chewed like no other land animal.

This clip shows the digital "chewing model" that the team from the University of Hull created.

Footage courtesy of Neil Curtis, University of Hull