The bones and teeth of an extinct animal provide scientists with information about the life history of that particular individual. Recently, 2 scientists analyzed the chemistry of 8 mammoth ( Mammuthus columbi ) and 4 mastodon ( Mammut americana ) teeth collected from Hamilton County, Ohio and Bullitt and Gallatin Counties, Kentucky–in other words, the Cincinnati area. They determined 11 of these animals spent their entire lives in what was to become the Cincinnati area. They also learned 7 of the mammoths ate different plant foods than the mastodons, but the diet from 1 individual mammoth did overlap with mastodon diets.
Hamilton County, Ohio
Mammoths and Mastodons lived year round in the Ohio River Valley. They were 2 completely different species of proboscidean.
Scientists are able to determine where an animal lived during its lifetime by measuring the ratio of strontium and strontium isotopes in their teeth. Strontium leaches from local bedrock into the water supply, and animals absorb the strontium into their bones when they drink. Different geographical regions exhibit different ratios of strontium isotopes, so it’s possible to figure out where an animal spent time during its life. A previous study of mastodon and mammoth teeth collected from Florida determined mastodons there migrated back and forth from central Florida to central Georgia, while Florida mammoths did not migrate. But this study suggests most of the mastodons that lived in the Ohio River valley did not migrate. However, there were exceptions. The strontium ratio from 1 specimen indicated this individual wandered north from either north Georgia or southern Tennessee to the Ohio River valley. The authors of this study estimated this could have been accomplished in as little as 5 days based on how fast modern elephants can travel.
The bone chemistry tells us mammoths mostly ate grass, while mastodons ate plants that grew in forested environments. But again there was 1 exception–1 mammoth that fed upon forest vegetation. During the Last Glacial Maximum much of this region was a cool arid steppe environment. After the nearby ice sheet retreated, the steppe was transformed into an open spruce parkland, then eventually an oak and hardwood dominated forest. This mammoth apparently adapted to the latter changes.
Mammoths and mastodons had no need to migrate away from the Ohio River. The rich floodplain habitat and numerous mineral licks provided enough nutrition to support year round populations of both.
Reference:
Baumann, Eric; and Brook Crowley
“Stable Isotopes Reveal Ecological Differences among now Extinct Proboscideans from the Cincinnati Region, USA”
Boreas 2015
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