Fossils point to penguin life in warm climate

Researchers reported Monday that they have unearthed two fossil penguins, one of which stood 5 feet tall, that lived in the warm climate of prehistoric Peru — a discovery that promises to change the way scientists think about penguins and cold weather.

Until now, most scientists thought ancient penguins first appeared more than 60 million years ago in cold habitats and did not move close to the equator until 8 million years ago. Large penguins, in particular, were thought to live only in colder climes.

The fossils, described online in the Proceedings of the National Academy of Sciences, disproved these theories.

"These discoveries tell us about the more complex relationship between penguin evolution and climate change," said study coauthor Sara Bertelli, a paleontologist at the Natural History Museum in Los Angeles.

The fossil penguins lived 30 million to 40 million years ago, just as the planet was beginning a cooling phase. The climate near the equator stayed warm the longest, with the temperature in Peru hovering around 79 degrees.

After reworking the penguin family tree to include the fossils, the scientists determined that modern penguins appeared 8 million years ago.

Earlier studies that analyzed DNA from living penguins placed the origin of the modern birds at 40 million years ago.

One factor that may have allowed temperature-sensitive penguins to migrate toward warmer climates was the separation of Antarctica from other continents approximately 40 million years ago. New ocean currents developed, bringing cold nutrient-rich water northward. Modern warm-weather penguins, such as the Galapagos penguin, still rely on these cold currents for their survival.

The scientists also said that according to their analysis, giant penguins were equally likely to appear in warm or cold climates.

Although the newly discovered giant penguin is not the record-holder — that honor goes to a 6 ½-foot-tall penguin fossil found on an island near Antarctica — it had a beak unlike any other known penguin. It probably used its long, spearlike bill to catch fish.

The shorter penguin was probably also a fish-eater. It was similar in size to a modern King Penguin, standing about 3 feet tall.