New comparisons of modern California condor bones to those found in Los Angeles’ La Brea Tar Pits show that two distinct species of these large vultures roamed the skies before the end of the last ice age, providing a compelling answer to a long-standing question.
At the end of the Pleistocene epoch about 10,000 years ago, when Earth was thawing out from the Ice Age, two types of condors competed over resources in what is now California, but it has been unclear if they were distinct species. The California condor seen in the skies today ultimately triumphed (though it is currently listed as Critically Endangered), while the others perished.
Paleontologists from Caltech studied the bones of deceased modern condors and the fossils of early condors preserved in the Pleistocene-era La Brea tar pits in Los Angeles, and found a definite size difference between the modern and Pleistocene bones.
"The ancients are decidedly bigger," said study leader Valerie Syverson, an undergraduate student at Caltech, noting particular differences in the femur, or thigh, bones.
The Pleistocene birds were heavier, with a longer, narrower skull and beak than the modern birds.
The ancient birds at first seemed to match a species first described in 1911, Gymnogyps amplus, but the bone that identified that species was much larger than either the modern condors (Gymnogyps californianus) or the Pleistocene birds, suggesting that there could have, at one time, been three different condor species.
"Based on the fact that the type specimen is outside the range for both of the groups, I wonder if we need to define a third species for the extinct La Brea condor," Syverson said.
The results of the study, presented Oct. 28 at the annual meeting of the Geological Society of America, also show that the ancient and modern condor species co-existed for some time and that the Pleistocene species may have lived at the same time as humans, because of the La Brea woman, the only prehistoric human found in the pits.
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