Gerald Mayr—AP By Associated Press 8:04 AM EST (NEW YORK) — Fossils from New Zealand have …
That’s nearly as old as the very earliest known penguin fossils, which were much smaller, said Daniel Ksepka, curator at the Bruce Museum of Greenwich, Connecticut. He has studied New Zealand fossil penguins but didn’t participate in the new study.
The new discovery shows penguins “got big very rapidly” after the mass extinction of 66 million years ago that’s best known for killing off the dinosaurs, he wrote in an email.
That event played a big role in penguin history. Beforehand, a non-flying seabird would be threatened by big marine reptile predators, which also would compete with the birds for food. But once the extinction wiped out those reptiles, the ability to fly was not so crucial, opening the door for penguins to appear.
Birds often evolve toward larger sizes after they lose the ability to fly, Mayr said. In fact, the new paper concludes that big size appeared more than once within the penguin family tree.
What happened to the giants?
Mayr said researchers believe they died out when large marine mammals like toothed whales and seals showed up and provided competition for safe breeding places and food. The newcomers may also have hunted the big penguins, he said.




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