Dino-Dining Dinosaurs
(Read the following information and complete the word frequency chart on Dinosaurs.)

Living with dinosaurs would have been terrifying—even for them. Some of the giant reptiles may have actually eaten each other.

About 70 million years ago, dinosaurs called Majungatholus atopus roamed the plains of Madagascar—a large island off southeastern Africa. The fearsome creatures grew up to 30 feet in length. And like many meat-eating predators, they had sharp, knifelike teeth with jagged edges.

The size and spacing of notches on the teeth of Majungatholus atopus match the grooves on bones of another member of the dinosaur species.

Many old animal bones found in Madagascar are scarred with grooved tooth marks, says Raymond R. Rogers, a paleontologist at Macalester College in St. Paul, Minn. This includes bones of the dinosaurs themselves.

To find out who made the tooth marks, Rogers and his colleagues measured the marks on some bone fossils. They also measured the spacing of notches on Majungatholus teeth. The two measurements matched almost exactly, the scientists report.

No other known animal could have made the same kind of grooves, Rogers says. The only other dinosaurs living in Madagascar at the time, five-foot-long Masiakasauraus knopfleri, were too small. And the island’s two meat-eating species of crocodile didn’t have the sharp, regularly spaced teeth necessary to make the marks.

Scientists still don’t know whether the dinosaurs actually killed each other or just ate the remains. But some reptiles today prey on each other. So it’s quite possible that certain dinos were safe nowhere, not even at home.