A PENGUIN big enough to look you in the eye is hardly what you’d expect to find in the tropics. But 36 million years ago, giant 1.5-metre penguins roamed the Peruvian coast.
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 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 didn’t start until about 34 million years ago, 2 million…
