A model of the diplodocus skull showing the distribution of stresses during biting. (University of Bristol)

A team of researchers, led by the University of Bristol and London's Natural History Museum, have used CT scans to try to figure out how one of the world's largest known dinosaurs was able to feed itself simply on plants.

They examined the skull of the diplodocus, a long-necked sauropod from the Jurassic period. Measuring more than 30 metres in length and weighing about 15 tonnes, it is one of the longest animals to have lived on Earth.

Since its remains were discovered 130 years ago, diplodocus has been the focus of scientific head-scratching because it managed to eat massive quantities of plants even though it had a strange skull and teeth construction. The diplodocus had a long snout and protruding teeth that would seemingly make it difficult for it to ingest enough food to keep itself alive.

"Sauropod dinosaurs, like diplodocus, were so weird and different from living animals that there is no animal we can compare them with," said Emily Rayfield, of Bristol University's school of Earth sciences, referring to the diploducus's skull formation.

"This makes understanding their feeding ecology very difficult."

The study, published Monday in the natural sciences journal Naturwissenschaften (Natural Sciences), involved creating a 3D model of a complete skull using data from a CT scan.

The model was then subjected to biomechanical tests — the same ones used in designing aeroplanes and orthopaedic implants.

The team discovered the diplodocus likely had a skull adapted to strip leaves from tree branches and that the combing and raking of these leaves from branches created about the same kind of stress on the skull bones and teeth that biting would.

The scraping technique is similar to the feeding behaviour of deer.