for National Geographic News
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"Eat or be eaten" may have been the mantra for Majungatholus atopus, a large, two-footed carnivorous dinosaur with a bump on its head that roamed Madagascar, the island off the southeast coast of Africa, about 65 million years ago.
Analysis of bones scored by tooth marks suggests Majungatholus was a cannibal that regularly dined on members of its own species and other dinosaurs. The rare, tooth-marked bones are the best evidence to date for a behavior probably common among dinosaurs but difficult to prove.
"I don't think this should be unexpected, but because of the nature of the fossil record we get such a limited window on this type of phenomenon. We have such a small sample of what really went down," said Raymond Rogers, a geologist at Macalester College in Saint Paul, Minnesota.
Rogers; together with his wife Kristina Curry Rogers, a curator of paleontology at the Science Museum of Minnesota; and David Krause, a professor of anatomy at Stony Brook University in New York; report their finding in the April 3 issue of Nature.
The trio analyzed hundreds of bones collected in Madagascar since 1993. Unlike most dinosaur fossils, many of these bones exhibit tooth marks. All of the tooth marks and many of the bones were identified as belonging to Majungatholus.
"When you ponder how difficult it is to find conclusive evidence at modern-day crime scenes, it's pretty amazing for us to realize that we have such direct evidence for animal interactions that occurred over 65 million years ago," said Krause, who helped to methodically sift through the evidence to rule out other potential suspects.
The wealth of material collected during the Madagascar expeditions, which are funded in part by a grant from the National Geographic Society Committee for Research and Exploration, is also giving scientists unprecedented detail on the lifestyle of Majungatholus.
"It is really exciting," said Kristina Curry Rogers. "It is a rare window into the world of dinosaurs whose behavior and biology were poorly known. Now we know it was a rabid meat-eater anxious to rip into the flesh of whatever it found."
Scientists believe that cannibalism was as common among dinosaurs as it is among modern animals. Lions, komodo dragons, foxes, and even pet dogs are among the animals that practice cannibalism today. But evidence for the behavior in the fossil record remains scarce.
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