Though it weighed 2 ounces and was 5 inches long, the chipmunk-like mammal that lived 123 million years ago had something its dinosaur predators didn't: middle ear bones partially independent of its jaw bone.Neat!
That evolutionary development helped Maotherium asiaticus have more sensitive hearing.
"This made it possible for mammals to be active in the night," said Dr. Zhe-Xi Luo, the Carnegie Museum of Natural History associate director of science and curator of vertebrate paleontology, in an e-mail from Germany.
"In the Mesozoic (Era), when dinosaurs dominated the world, this is a key adaptation for the survival of mammals," he said.
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