SCI/TECH: Discovery Shows Early Mammals Fed on Dinosaurs

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A team led by scientists from the American Museum of Natural History in New York City discovered bones of a beaked, two-legged dinosaur in the stomach of a cat-sized animal that died about 130 million years ago in China's northeastern Liaoning region. At the same site the team also unearthed the remains of the largest primitive mammal ever found, a creature roughly as big as a beagle.

The two findings, reported yesterday by the journal Nature, suggest the two types of creatures may have competed fiercely for food and habitat.

The announcement raises key questions about a long-held evolutionary theory that assumes mammals during the dinosaur era were small because it was the only size that allowed them to survive amid the dangerous world of predatory dinosaurs. Scientists have long reasoned mammals didn't begin a true growth spurt until after dinosaurs were wiped out 65 million years ago. The discovery raises the possibility that mammals influenced the dinosaurs' evolution, not just the other way around.

The mammals lived during the Mesozoic era from about 280 million to about 65 million years ago that is largely known as the age of the dinosaurs. Although scientists have found teeth and other evidence suggesting that mammals might have been bigger than first believed during this period, it was sparse and incomplete. The team's findings are by far the most extensive skeletons ever


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