A US study on Monday found that Neanderthals, prehistoric cousins of humans, ate grains and vegetables as well as meat, cooking them over fire in the same way homo sapiens did.

The new research published in the Proceedings of the National Academy of Sciences (PNAS) challenges a prevailing theory that Neanderthals' over reliance on meat contributed to their extinction around 30,000 years ago.

Researchers found grains from numerous plants, including a type of wild grass, as well as traces of roots and tubers, trapped in plaque buildup on fossilized Neanderthal teeth unearthed in northern Europe and Iraq....