Ancient El Niños triggered Baja bunny booms

Date:

June 4, 2015

Source:

University of Utah

Summary:

At times during the past 10,000 years, cottontails and hares reproduced like rabbits and their numbers surged when the El Niño weather pattern drenched the Pacific Coast with rain, according to an analysis of 3,463 bunny bones.

The study of ancient rabbit populations at a Baja California site may help scientists better understand how mammals that range from the coast to the interior will respond to climate change, says anthropology doctoral student Isaac Hart. He is first author of the study to be published in the July issue of the journalQuaternary Research.

During the past 10,000 years, the number of El Niños per century "correlates very strongly with the total rabbit population in Baja California, as well as relative abundance of the moisture-loving species of rabbits," Hart says.

"There weren't many El Niños from 10,000 to 5,000 years ago," perhaps zero to two per century, says the study's senior author, anthropology professor Jack Broughton. "After 5,000 years ago, there was a relatively dramatic increase in frequency of El Niños in Baja, and the rabbits go through the roof."

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