La Brea fossils
April 11, 2014

Role Of Climate Change In Extinction Of Ice Predators Examined

[ Watch the Video: Research Shows Climate Change Drove Evolution Of Ice Age Predators ]

redOrbit Staff & Wire Reports - Your Universe Online

For the first time, the authors of two new scientific papers have documented the impact that global climate change had on the evolution of Ice Age-era predators whose remains were discovered in California’s La Brea Tar Pits.

The authors of the two studies explain that climate warming helped drive the evolution of creatures such as dire wolves and saber-toothed cats that lived between 50,000 and 11,000 years ago. Unstable conditions during that time caused significant changes to those predatory creatures, they said.

“Different tar pits at La Brea accumulated at different times,” explained Marshall University assistant biology professor F. Robin O'Keefe, lead author of a Palaeontologia Electronica report on the dire wolves. “When we compare fossils deposited at different times, we see big changes. We can actually watch evolution happening.”

In their study, O’Keefe and his colleagues explain that La Brea dire wolves became smaller and more graceful during the end of the last ice age. Those evolutionary changes allowed them to hunt smaller prey as the temperatures began to warm up and the glaciers started to recede.

Similar climate-related changes occurred in saber-toothed cats as well, according to Des Moines University assistant anatomy professor Dr. Julie Meachen and the other scientists behind a recently published Journal of Evolutionary Biology study.

“Saber-toothed cats show a clear correlation between climate and shape. Cats living after the end of the Ice Age are larger, and adapted to taking larger prey,” Meachen, who worked with O’Keefe and Rudyard Sadleir of St. Xavier University in Chicago, Illinois on the study, said in a statement Wednesday.

“We can see animals adapting to a warming climate at La Brea,” added O'Keefe. “Then humans show up and all the big ones disappear. We haven't been able to establish causality there yet. But we are working on it.”

The researchers emphasize that additional research is needed to explore the association between climate change and evolutionary changes, as there are many questions that have not yet been answered. For example, why do predators change in the specific ways that they do? How important are factors other than climate in the process, and what role did the arrival of humans play in the post-Ice Age mass extinction of these creatures?

“There is much work to be done on the specimens from the tar pits. We are working actively to bring together the researchers and resources needed to expand on these discoveries,” said John Harris, chief curator at the Page Museum at the La Brea Tar Pits. “Climate change is a pressing issue for all of us, and we must take advantage of what Rancho La Brea can teach us about how ecosystems react to it.”

Image 2 (below): A new dire wolf study documents the impact of climate change on La Brea Tar Pits predators for the first time. Credit: Dr. Frank O'Keefe, Marshall University