July 24, 2014

Traveling Far From Home Wasn’t Preferred By Cincinnati’s Ice Age Mammoths And Mastodons

April Flowers for - Your Universe Online

Around the end of the last ice age roughly 10,000 years ago, mammoths and mastodons lived in North America. According to the Field Museum of Natural History, the 14-foot tall mammoths migrated to North America from Europe across the Bering Land Bridge. The smaller, heavier mastodons, however, were indigenous to the continent. Both of these fuzzy relatives to modern-day elephants once lived in the Greater Cincinnati area during this time.

A new study from the University of Cincinnati, led by assistant professor of geology and anthropology Brooke Crowley, reveals that the ancient proboscideans were likely year-round residents and not nomadic migrants as previously thought.

The findings, published in Boreas, demonstrate that each group even had their own preferred locations based on the availability of favored foods. "I suspect that this was a pretty nice place to live, relatively speaking," Crowley said in a recent statement. "Our data suggest that animals probably had what they needed to survive here year-round."

Gaining more knowledge about the different behaviors of mammoths and mastodons could lead to benefits for their modern-day relatives, the African and Asian elephants — both of which are on the World Wildlife Fund's (WWF) endangered species list. Crowley says that understanding the variability of different types of ancient elephants might help with ongoing conservation efforts to protect the Asian and African elephants from threats such as poaching and habitat destruction.

"There are regionally different stories going on," Crowley said. "There's not one overarching theme that we can say about a mammoth or a mastodon. And that's becoming more obvious in studies people are doing in different places. A mammoth in Florida did not behave the same as one in New York, Wyoming, California, Mexico or Ohio."

Many recent studies have involved fossilized teeth, such as the Arctic tiger shark teeth used to determine Arctic Ocean salinity reported by redOrbit earlier this month. Drilling the tooth's surface to analyze the stable carbon, oxygen and strontium isotopic signatures can reveal a great deal about an animal's environment. Crowley and her colleague, Eric Baumann, used museum specimens of molars of four mastodons and eight mammoths collected in Southwestern Ohio and Northwestern Kentucky.

A different story is written into each element in the tooth. Carbon reveals the animal's diet, while oxygen defines the overall climatic conditions of the environment. Strontium can also provide a map of how much the animal traveled during the tooth's formation.

"Strontium reflects the bedrock geology of a location," Crowley said. "So if a local animal grows its tooth and mineralizes it locally and dies locally, the strontium isotope ratio in its tooth will reflect the place where it lived and died. If an animal grows its tooth in one place and then moves elsewhere, the strontium in its tooth is going to reflect where it came from, not where it died."

Some of the key findings of this study include:

- Mammoths favored grasses and sedges, while mastodons liked tree and shrub leaves.

- With the exception of one animal, strontium matched the local water samples from where the tooth was collected. This indicates that they were less mobile and migratory than previously assumed.

- Differences in carbon and strontium in the species indicates that the mammoth and mastodon populations did not inhabit the same localities.

- Grasses were more abundant closer to the retreating ice sheet, making it a favored location for the mammoths. Mastodons, on the other hand, preferred a more forested habitat farther away.

“As a geologist, questioning the past is one of the most interesting and exciting things to do,” says Baumann, an environmental geologist with a contractor for the U.S. Environmental Protection Agency. “Based on our data, mammoths and mastodons seemed to have different diets and lived in different areas during their lives. This is important because it allows us to understand how species in the past lived and interacted. And the past is the key to the present.”

Crowley intends to continue her study into how strontium isotopes can be used to explore megafauna.