UC study: Prehistoric horses were homebodies

Some zebras today trek hundreds of miles to find food and water, but prehistoric horses in parts of North America did not have to undertake epic migrations, according to a new study by the University of Cincinnati.

The findings suggest Florida was something of a horse paradise 5 million years ago, providing everything horses could want in a relatively small area.

The study was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology. It demonstrates UC's commitment to research as part of its strategic direction, Next Lives Here.

Plains zebras and Mongolian wild horses take on epic migrations each year to find water or green grass.

The Mongolian wild horse, also known as a Przewalski’s horse, travels as much as 13 miles per day. And Burchell’s zebras in southern Africa are known for their seasonal migrations that take them as far as 300 miles and back as they follow the rains to green grass.

But geologists in UC’s McMicken College of Arts and Sciences found that prehistoric horses in coastal Florida lived and died within a comparatively small area.

“It seems that these horses in Florida were relatively sedentary. They didn’t travel far distances,” said Jenelle Wallace, a UC graduate and lead author of the study.

The study was the basis of Wallace’s master’s thesis. Today, she works as an engineering geologist for the New York State Department of Environmental Conservation.

“My third spoken word after mom and dad was horse,” Wallace said. “I’ve loved them ever since I was little.”

UC geology professors and study co-authors Brooke Crowley and Joshua Miller have used this technique to track the movements of other animals, both living and prehistoric. Crowley used bones collected from the nests of secretive goshawks to map the birds’ travels in Madagascar. She and Miller also are studying the movement of Ice Age mastodons in North America.

“There is a lot of opportunity for expanding the use of strontium to look at a variety of animal groups, time periods and locations,” Crowley said.

The study examined seven species of horse along with two known leaf-eaters: a prehistoric tapir and a distant relative of elephants called a gomphothere.

The results were surprising, researchers said.

Of all the animals studied, the tapir seemed to have the widest geographic range based on the high variability of strontium found in its teeth. But given that modern tapirs have relatively modest home ranges, researchers said it’s more likely that prehistoric tapirs consumed river plants that absorbed nutrients carried far downstream.

Crowley, who also teaches in UC’s Department of Anthropology, said studies like this shed light on the habitat needs of animals long before they were influenced by human activities.

“Having a deep perspective is really important for understanding a species’ needs in conservation and management,” Crowley said. “If we just look at a narrow window of time — like 50 or 100 years — we don’t get a good picture of a species when it’s not in crisis.”

Using the geologic record, researchers can piece together how animals interacted, what allowed them to thrive and what ultimately caused them to perish, she said.

“By using this technique, we can answer questions in a way we couldn’t otherwise,” Crowley said. “That’s the cool thing about geochemistry. You can unlock secrets in teeth and bones.”

Featured image at top: UC researchers studied descendants of Eohippus depicted in this 1913 drawing by illustrator Robert Bruce Horsfall. Graphic/Wikimedia Commons