When giant penguins roamed the tropics

 作者:仲长谛愕     |      日期:2019-02-28 04:07:02
By Jeff Hecht (Image: Daniel Ksepka) A penguin big enough to look you in the eye is hardly what you would expect to find in the tropics. But 36 million years ago, giant 1.5-metre penguins roamed the Peruvian coast just 14 degrees south of the equator. Large size in penguins is thought to be an adaptation to conserve body heat, so Mario Urbina of the National University of San Marcos in Lima, Peru, was surprised to find that the giants, named Icadyptes salasi, lived in the tropics at a time when Earth was much warmer. The global cooling that covered Antarctica with ice sheets did not start until about 34 million years ago – two million years after Icadyptes had died out. Icadyptes is the third-largest giant penguin ever found, and the most complete. Its beak is over two times the length of its skull, the longest ever seen on a penguin. A second fossil from a 42-million-year-old deposit, Perudyptes devriesi, was the size of a living king penguin. “We don’t know how the large penguins would have thermoregulated on land,” says Julia Clarke of North Carolina State University in Raleigh, US, who worked with Urbina to analyse the fossils. They probably spent most of their time in the water, she says. Journal reference: Proceedings of the National Academy of Sciences (DOI: