While our local bears are active and enjoying summer in Whistler, their long winter hibernation has several fascinating traits. Their unusual physical characteristics during their long sleep may provide researchers with insights that have the potential to benefit their human neighbours’ health (yet another reason for us to remain-bear-friendly).
It is almost the opposite for bears. Several researchers have recently studied hibernating bears and what follows is a brief summary of their findings.
Hibernating bears, grown fat from summer feasting, do not eat, drink, urinate or defecate while they are hibernating. But they lose no muscle mass from inactivity. Platelets in the bears’ blood become less sticky, acting as a natural blood thinner, the researchers found, perhaps to counteract blood clots that could form during long periods of immobility. The bears’ metabolism drops to 25 percent of its normal state and their kidneys stop functioning, yet they do not have kidney failure. Bears’ heart rates slow sharply during hibernation, from about 75 beats a minute to as few as 10, with pauses that sometimes lasted 19 seconds or more.
The researchers were surprised to find that bears’ body temperature drops only slightly during hibernation. In other animals, there is generally a more significant change in body temperature when there are metabolic changes. Anytime the bears’ body temperatures dropped to 86 degrees Fahrenheit, they shivered to warm up, he said.
The research might one day help doctors treat stroke patients, who could benefit from a lowered brain temperature in the hours after a stroke.
There have also been discussions regarding replicating hibernation for humans on long space voyages.
The new wave of hibernation research is of particular interest to scientists studying obesity. Obesity in humans is associated with resistance to insulin, a hormone that regulates glucose in the blood, and Type 2 diabetes. Bears also show insulin resistance, studies find, but do not develop diabetes in the classic sense.
“Obese bears are healthier; in fact, they are more reproductively fit,” said Heiko T. Jansen, a professor at the College of Veterinary Medicine at Washington State University. “They have all the advantages, which is so counterintuitive to human biology.”
As if our furry friends were not already cool enough we now have many more reasons to admire them! Let’s ensure we keep them safe as they may in turn save some of us.