Bone bite marks reveal dinosaur predator-prey dynamics

WASHINGTON — On the perilous Jurassic Period landscape of western North America, it was good to be big. Your life may have depended upon it.

Paleontologists have conducted a study scrutinizing bite marks left by meat-eating dinosaurs on the bones of sauropods — the familiar plant-eating dinosaurs with long necks, long tails and four pillar-like legs that were the largest land animals around — about 150 million years ago. The examination offered insight into predator-prey dynamics during the dinosaur age.

Of about 600 bones checked, bite marks — often deep grooves left in stout bone — were detected on 68 of them, spanning 40 individual sauropods and representing at least nine species.

The nature of the bites led the researchers to an intriguing conclusion. These marks appear to have been made not by predators that had hunted and killed adult sauropods but rather through scavenging by meat-eaters that came across the bodies of sauropods already dead from causes like old age or infirmity.

It simply may have been too risky, they said, for a predator - even one weighing multiple tons - to try to bring down an adult sauropod perhaps five to 10 times more massive like Brachiosaurus.

"While it must have happened occasionally, we can't find any wounds that would likely be the result of predation attempts," said paleontologist David Hone of Queen Mary University of London, who helped lead the study published this week in the journal Peerj Life & Environment.