Oklahoma black bear population monitored

Tuesday, February 18, 2014

Oklahomans are welcoming a break from the frigid conditions that swept the state recently. No one likes to be cooped up, but inside and away from the freezing temperatures is the only way to go.

For some wildlife, there is hardly any break from the weather, while others, like Oklahoma black bears, enter their dens in December or January and typically remain there for several months.

“Black bears in Oklahoma will find a cozy spot and sleep through cold winters,” said Sue Fairbanks, assistant professor in Oklahoma State University’s Department of Natural Resource Ecology and Mangement. “They don’t eat or drink while denned, and their heart rate and metabolic rate drop. But, their body temperatures don’t decrease as much as small hibernators, like chipmunks and skunks.”

Female bears will give birth to cubs in their winter den and nurse them for almost three months before the family emerges. The quality of these dens is crucial and may be an important habitat feature that affects reproduction.

“Oklahoma has two black bear populations,” Fairbanks said. “One group is in the Ouachita Mountains of southeast Oklahoma, while the other is in the Oklahoma Ozark in the east central part of the state.”

Members of OSU Cooperative Fish and Wildlife Research Unit, David Leslie and Sara Lyda, have been studying the expanding black bear population since 2011 in conjunction with the Oklahoma Department of Wildlife Conservation. By tracking radio-collared bears to their winter dens, the researchers have found bears use rock crevices, hollow trees, holes dug into the ground under the root ball of fallen trees and a variety of shelters for dens.

Occasionally, a bear will abandon a den during winter in search of a new one. To help discover why they do this, the research team came up with an idea.

“A new component of the project we will begin this winter is a study of the temperature profiles of different types of dens used by the bears,” said Fairbanks. “This year, when we track bears to the dens to change their collars and determine cub production, we will attach a tiny ibutton inside the den and one outside.”

The ibuttons are programmed to record temperature every four hours beginning at midnight.

“This will help determine the warmth provided by different types of dens, and determine whether pregnant female bears choose warmer dens than other bears,” she said. “The more we know about what constitutes a safe, warm den for the birth and survival of black bear cubs, the better we can identify and manage good black bear habitat.”