The 46-foot-long (14-meter-long) Brontomerus mcintoshi had an immense blade on its hipbones where strong muscles would have attached, according to a new study.

"These things don't happen by accident—this is something that's clearly functional," said study co-author Mathew Wedel.

The team suspects the dinosaur—a type of sauropod, or plant-eating, four-legged lumberer—used its massive legs to either maneuver over hilly ground or deliver "good, hard" kicks to predators, said Wedel, assistant professor of anatomy at Western University of Health Sciences in Pomona, California.

"I could only imagine how ill-tempered these sauropods would have been," Wedel said—as are most birds, dinosaurs' modern-day descendants.

In both cases, "you've got a little brain, you're permanently paranoid about all these meat-eaters around, and you're trying to protect