Mastodon’s fang reveals migration patterns in North America

Northeastern Indiana served as a summer mating ground for mastodons, and the study found that this solitary creature migrated annually north of its home during the winter months for the last three years of its life. The researchers estimated that the ancient animal was about 34 years old when it died.

“Using new modeling techniques and a powerful geochemical toolkit, we were able to show that males of large animals such as Buesching migrate each year to their mating grounds,” Miller said.

Daniel Fisher, co-leader of the study, helped excavate the mastodon 24 years ago. He is Professor of Paleontology at the University of Michigan, and Director of the University of Michigan Museum of Paleontology.

Fisher cut a long, thin section from the center of the right canine, which is 9.5 feet (3 meters) long. Like the study of tree rings, analysis of a mastodon’s tusk revealed how it interacted with its landscape as a teenager as well as during the last years of its life.

“You have a whole life extended ahead of you in that tusk. The animal’s growth and development, plus its history of changing land use and changing behavior — all of that history is captured and recorded in the structure and formation of the tusk,” Fisher said.

When he was young, the mastodon was stuck close to home with a female-led herd in central Indiana before breaking off and venturing out on his own—just like modern elephants. As a lone rover, the mastodon drove 20 miles (32 kilometers) each month.

canine analysis

Migration was critical for mastodons to find places where they could breed while living in harsh, cold climates. But it was difficult for researchers to determine their geographical ranges.

Searching for oxygen and strontium isotopes within mastodon tusks reveals some of this insight.

Mastodon tusks, like elephant tusks, have new growth layers that form near the center throughout their lives. Information about the time of their birth can be found stored at the tip of the canine, while their death is in the layer at the base of the canines.

When mastodons chewed on bushes and trees and drank water, the chemical elements from their meals became stored in their canines as well.

Chemical analysis of microsamples from different canine layers of Buesching’s mastodon has been associated with geographic locations where the elements have changed according to the landscape, as well as with seasonal fluctuations. This data was put into a motion model that the researchers developed to essentially track when, where and how it traveled.

“Every time it got into the warm season, the Buesching mastodon would go to the same place — bam, bam, bam — repeatedly. The clarity of this signal was really unexpected and exciting,” Miller said.

Next, the researchers want to study the canines of other animals to see if they can make similar discoveries.