Mammoths and mastodons (which are different, contrary to popular discourse: mastodons lived from about 30 million to 12,000 years ago, while mammoths lived from about 5 million to 10,000 years ago) liked to stay in one place, if that one place was Ohio/Kentucky.

Researchers studied the enamel in mammoth and mastodon molars to learn about their diet (through carbon analysis), the climate at the time (oxygen analysis), and their location while alive (strontium analysis). Traces of strontium, a metallic element, revealed that these titanic mammals lived almost exclusively in the Ohio Valley for their whole lives. It probably had everything these giants needed: grasses, sedges, forests, and other sources of tasty vegetation.

The scientists matched variation in strontium isotopes to similar variation in strontium in the bedrock of Ohio and Kentucky (by testing water samples), and found that only one mastodon (out of 8 mammoths and 4 mastodons) traveled in to the Ohio Valley before settling down. Perhaps that mastodon was the LeBron of his herd.