Study finds hibernating black bears could provide answers to human health concerns

Can hibernating bears help with human health concerns? Wildlife professor Mike Vaughan, who studies bears at the Virginia Bear Research Center in Blacksburg, says he thinks so.

The bears at the center are considered nuisance bears, which were captured by the Virginia Department of Game and Inland Fisheries. They are kept for three to four months of hibernation then released back into the wild. In their dormancy, they become the perfect study subjects for Vaughan and his students.

   

Ben Augustine measures a bear cub's head. Ben Augustine takes black bear cub measurements at the Virginia Bear Research Center.

The researchers also seize the opportunity to learn about bear reproductive physiology, and cub growth and development.

One study being conducted on the snoozing bears aims to learn more about human bone loss.

"While denned, bears don't have much opportunity to exercise their muscles or bones," notes Vaughan, who is a member of the faculty in the College of Natural Resources.

   

A bear cub chews on Mike Vaughan's finger. Michael Vaughan (left), Colleen Olfenbuttel (center), and Ben Augustine (right) work with bear cubs at the research center while their mothers are still in hibernation.

Humans who are on bed rest don’t have that opportunity either, but the inactivity can lead to osteoporosis, which bears don't develop. In an effort to understand this difference and thus help humans, Vaughan started out drawing blood from the bears and sending it to Seth Donahue, a biomedical engineer at Michigan Technological University. Donahue examines the blood hormones responsible for bone formation and breakdown.

"Donahue has found that even though bears do lose some bone material while denned, they also continue to make bone material," Vaughan says. "And once out of the den, they make up any deficiency very quickly." The ongoing collaboration between the two universities, he adds, is pursuing how the bears manufacture the bone cells while on "autopilot."

Now the researchers are taking bone biopsies on some bears at three stages — before, during, and after denning — to measure bone growth to see if that correlates with hormone production during those stages.

   

A bear cub gets his paw measured. To calculate growth rates, the research center takes measurements of bear cubs before mother and cubs are returned to the wild.

Dr. Otto Lanz, associate professor in the Virginia-Maryland Regional College of Veterinary Medicine, is helping with the bone biopsies.

"The bone growth study is a pilot study as we try to get support for a more comprehensive study," says Vaughan.

Potential for humans to benefit from the bear research exists in other ways. One marvel of the mammals is that they don't eat, drink, or expel waste the entire time they are denned — which means, Vaughan notes, that "kidney function essentially stops; humans can't do that."

"If we could fully understand how bears recycle waste in their bodies without kidney function, it could have human health implications," Vaughn says.

Bears also store a significant amount of fat in the fall to sustain them through their hibernation, yet they don't experience the same cholesterol buildup as humans do. Understanding why could be a boon.

The bear research team also has made discoveries about bone metabolism and hormonal changes in bears during hibernation that could yield valuable insights into depression in humans.

Vaughan, who has worked with bears for over 25 years, says the possible applications of the bear research are fascinating.

"When I first started working with bears, some of the human health implications were just coming to light," he says. "I had no idea at that time that bears could play such an important role in human health.”

  • For more information on this topic, contact Lynn Davis at (540) 231-6157.

Bear population research

Vaughan is also studying the dynamics of Virginia's hunted black bear population.

Virginia hunters harvest about 500-600 bears each year: Most of what is known about Virginia's hunted bear population comes from harvest data.

Since bear birth rate and population density are unknown, the research aims to provide demographic information so that wildlife managers can better manage the population.

About black bears

   

Colleen Olfenbuttel holds a black bear cub. Colleen Olfenbuttel holds a black bear cub.

Black bears are:

  • Approximately 4 to 7 feet tall;
  • 2 to 3 feet tall at the shoulder; and
  • Known to range in color from black or brown to blonde.

There are 16 recognized subspecies of American black bear.

Other fisheries and wildlife sciences research

Learn more about research from the Department of Fisheries and Wildlife Sciences.

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