Nature Lab

By Bonnie Chasteen | November 1, 2017
From Missouri Conservationist: November 2017

Each month, we highlight research MDC uses to improve fish, forest, and wildlife management.

Wildlife Management: Tooth Aging

Analyzing an animal’s tooth can reveal its age and other clues about its life history.

The biologist worked quickly and carefully to extract the sedated sow bear’s tiny upper premolar. “We send the premolars to a lab in Montana,” said MDC furbearer biologist Laura Conlee. “They will tell us how old she is, when she began having cubs, and how many times she has had cubs.”

Conlee’s team tracks sow bear age and reproductive history as part of their annual monitoring efforts. “When the bear population reaches 500 animals, we will recommend a hunting season to the Commission,” she said.

Conlee and many other MDC resource scientists rely on Matson’s Lab in Manhattan, Montana, for its cementum age analysis (CAA) services. “With this technique, we prepare and stain the cementum, a material that grows in annual layers around the tooth roots of all mammals,” said Carolyn Nistler, who owns the lab with her husband, Matt. “The dark-staining rings form during the winter, and the light-staining rings form during the spring and summer growth seasons. In the case of a sow bear, light, narrow growth rings show the years she had a cub.”

MDC sends Matson’s Lab the teeth of several other game mammals, including bobcats, river otters, and white-tailed deer. In these cases, however, teeth are collected during annual harvest seasons. “CAA helps us know exactly how old an animal was when it was harvested,” said MDC Cervid Program Supervisor Barbara Keller. “This data helps us create accurate models of Missouri’s game-mammal populations, so we can set appropriate regulations to ensure sustainable harvest. It’s all management driven.”

Tooth Aging at a Glance

MDC sends 4,500 wildlife teeth to Matson’s Lab yearly. In the lab, slicing, staining, and magnification show annual growth rings

Other mammals we tooth-age: otter, deer, and bobcat.

Browse more research projects at

This Issue's Staff

Editor - Angie Daly Morfeld

Associate Editor - Bonnie Chasteen

Staff Writer - Larry Archer
Staff Writer - Heather Feeler
Staff Writer - Kristie Hilgedick
Staff Writer - Joe Jerek

Creative Director - Stephanie Thurber

Art Director - Cliff White

Designer - Les Fortenberry
Designer - Marci Porter

Photographer - Noppadol Paothong
Photographer - David Stonner

Circulation - Laura Scheuler