Mastodon Tusks Reveal the Unpredictable Life of an Ancient Beast

An American mastodon inhabited what is now the Midwest more than 13,000 years ago. Every year, he went to the same location in northeast Indiana, which is thought to be a breeding habitat for these birds. In combat, he was killed there.

According to new research published in the Proceedings of the National Academy of Sciences, scientists were able to determine the mastodon’s exact location and death date by analyzing chemical traces found in his tusk. Their methods provide light on a previously unknown elephant cousin that inhabited North America before becoming extinct.

The Buesching mastodon, titled after the family farm where it was discovered in 1998 and currently on exhibit at the Indiana State Museum, was examined by scientists. A.K.A. “Fred,” his tusks serve as a time capsule for the animal’s whole existence, allowing researchers to piece together details from certain days, weeks, and years. Because of this, researchers were able to collect samples from the tusks of adolescent and adult elephants to study how their migratory patterns have altered over time.

Investigating the migration of the animal

Traces of strontium and oxygen isotopes were found in the tusks as part of this migration-detection investigation. This study’s co-author, paleoecologist Joshua Miller, characterized strontium isotopes as spreading a trail of evidence all across the terrain. Isotopes of strontium leak from rocks and into the land and water around them. He said that those isotopic signals are incorporated into the plants when they consume these nutrients. That flora would be a tasty treat for our hungry mastodon, whose tusks would bear the imprint of the area where they grew.

Another step is needed to analyze these geographic coordinates and map them onto the landscape: a map showing how the strontium isotopes vary with elevation. One of the study’s co-authors, Brooke E. Crowley, who is also from Cincinnati, had previously generated a similar map, on which the researchers built. Using isotopes of oxygen, researchers were able to identify the seasons in which Fred traveled. When he drank from neighboring ponds and streams, he was ingesting air isotopes that recorded the current season.

It was possible to track this animal’s movements with the use of sophisticated statistical modeling. This mastodon spent most of his childhood in the same area. There were signs of nutritional stress throughout his adolescence, which is typical in male elephants who have separated from their matriarchal herds and are left to care for themselves.
From the time he was 29 to 32, this mastodon’s life took a dramatic turn. When he suddenly started traveling at a high rate of speed, he was showing indications of several wounds. In spite of this, he continued coming to northeast Indiana every year—a place he had never visited as a teenager. In the late spring and early summer of that year, he was injured there, which is a strong indication that it was a breeding area.