SOURCE: Western University of Health Sciences

Western University of Health Sciences

February 21, 2012 19:01 ET

In the Footsteps of Prehistoric Elephants

WesternU Professor Co-Authors Study of Trackway Site

POMONA, CA--(Marketwire - Feb 21, 2012) - Seven-million-year-old footprints from the Arabian Desert provide the oldest known evidence of how elephant ancestors interacted socially.

The Mleisa1 site in the United Arab Emirates features exceptionally long trackways of a single herd of at least 13 individuals. The herd walked through mud and left footprints that hardened, were buried, and then re-exposed by erosion. Analysis of trackway stride lengths reveals the herd contained a diversity of sizes, from adults to a young calf, making this the earliest direct evidence of social structure in prehistoric elephants ever discovered.

An international team from Germany, France, the United States and the United Arab Emirates -- including Western University of Health Sciences Assistant Professor Brian Kraatz -- will publish the study in Biology Letters on February 22, 2012.

Primary author Faysal Bibi is a researcher at the Institut International de Paléoprimatologie, Paléontologie Humaine : Évolution et Paléoenvironnements in Poitiers, France, and the Museum für Naturkunde in Berlin, Germany. Co-authors are Brian Kraatz, assistant professor of anatomy at WesternU's College of Osteopathic Medicine of the Pacific; Nathan Craig, assistant professor of anthropology at Pennsylvania State University; Mark Beech, Abu Dhabi Authority for Tourism and Culture; Mathieu Schuster, research associate, Universite de Strasbourg, France; and Andrew Hill, professor of anthropology, Yale University.

"Basically, this is fossilized behavior," Bibi said. "This is an absolutely unique site, a really rare opportunity in the fossil record that lets you see animal behavior in a way you couldn't otherwise do with bones or teeth."

Not only were the prehistoric elephants herding, but a 260m-long trackway of a solitary male at the same site indicates they also differentiated into solitary and social groups, and that these might have been sex-segregated just like in elephants today. In living elephants, adult females lead the herds while males disperse at sexual maturity and come back only to mate; such behavior is also suggested at the Mleisa 1 site.

"It's significant primarily because it allows us to put a scale on how old this behavior is," Kraatz said. "Matriarchal herding is a behavior that is not unique to elephants, but it's rare overall -- and dramatic in elephants. There's really been no fossil evidence of matriarchal society in elephants, or really many other groups for that matter. It allows us to extend this behavior back at least 7 million years in history. Not only is this telling us about how animals are evolving, but it's also giving us insight into how and when behavior is evolving."

The Mleisa1 Trackway Site Press Page features the full article, supplementary information, high-resolution images, author biographies and additional contact information: http://mleisa1.wordpress.com/

Contact Information