Veggie dinosaurs also liked a shellfish snack

Paris : Some dinosaurs may not have been the strict vegetarians that palaeontologists thought they were.

New analysis of fossilised dinosaur dung suggests some herbivorous dinosaurs may have also eaten crustaceans, according to a new study published Thursday in the Nature journal Scientific Reports.

The egg-laying creatures may have turned to the snack when they were breeding and in need of extra protein. 

"It was surprising to find that the dinosaurs had eaten animal food in the form of crustaceans," said author Karen Chin, an associate professor and curator of palaeontology at the University of Colorado's Museum of Natural History.

"We don’t yet know what kind of crustaceans they were, but hope to find more (fossilised dung) specimens that have particular features that will allow us to identify them." 

The findings challenge common presumptions of the feeding habits of some herbivorous dinosaurs.

Their diets may have been more akin to that of birds, which often seek extra protein and calcium during the breeding season, than to that of large herbivorous mammals, such as elephants and giraffes, the researchers suggest. 

Dinosaurs were the monarchs of Earth for 160 million years until a space rock collided with the planet 65.5 million years ago and wiped out those confined to land. 

The survivors, which could fly, are the direct ancestors of today's birds.

Chin and her colleagues found many examples of shell-like material within coprolites -- fossil faeces -- in the Kaiparowits rock formation in southern Utah, which date from the late Cretaceous period.

The research suggests the dinosaurs consumed sizeable crustaceans sheltered in rotting logs.

It is not known which species the dung came from, but the authors believe it could be hadrosaurs -- duck-billed behemoths that could grow to over eight metres (26 feet) in length.