Saturday, January 30, 2010

Crane brains and behaviors 1 - the evolutionary legacy

Crane brains control crane behavior. To understand the present-day crane brain, we need to appreciate its evolution.

Cranes are members of Gruiformes - an ancient order of
birds. One chicken-sized gruiform (fossil to the right) lived 30 million years ago on the grasslands of present-day France1. The famous ornithologist Alexander Wetmore identified fossil leg bones from the Paleocene prairies of Nebraska and Kansas as those of Sandhill Cranes from 7 million years ago2, an argument for cranes as the oldest bird species alive today. There are no fossil skulls found for these Paleocene Sandhills, but their brains, like those of modern birds, must have carried a legacy of adaptations acquired through natural selection over hundreds of millions of years.