Who did the dinosaurs' demise benefit to?

After the Dinosaurs’ Demise, Many Mammals Seized the Day

When the dinosaurs are away, the mammals will play. That’s the basic idea behind the “nocturnal bottleneck” hypothesis, a concept proposed in 1942 that suggested mammals could have only survived in a dinosaur-dominated world by avoiding the sharp-toothed beasts during the day and coming out at night. Mammalogists have long thought the earliest shared ancestor of all mammals was nocturnal, and now a study published Monday provides a potential date for when the furry creatures stopped cowering in the shadows and started venturing into the daylight. The researchers found that the first mammals to be active during both day and night appeared around 65.8 million years ago, just 200,000 years after the extinction event that led to the demise of most dinosaurs. They were most likely the ancestors of even-toed ungulates, like today’s cattle, llamas and hippopotamuses, as well as the cetaceans like whales and dolphins. “In evolutionary time 200,000 years are hardly anything. It’s almost immediately,” said Roi Maor, a doctoral student at Tel Aviv University in Israel and University College London, and lead author of the paper that appeared in Nature Ecology & Evolution. They also found the first mammals that were clearly diurnal, or only active during the daytime, appeared about 52.4 million years ago, some 13 million years after the dinosaurs died out. Among these...Read more...

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