Grizzly Bear Refuge Report

November 21st Special Refuge Update
“Grizzly Bears are a medical Marvel”

Temperatures have been rather chilly at the refuge and the ranges within Boo’s den have been between -3.7°-9.2°C. These temperatures may seem chilly to us however, Boo finds these temperatures rather ideal for his heavy body condition. The extra fat he worked so hard to build up will keep him protected from the cold and provide his body with the most basic needs such as hydration as winter progresses. During hibernation, bears keep their body temperatures above 31°C or 88°F. During their active season the normal range of body temperature is 37.7°-38.3°C or 100°-101°F. Their metabolic rate slows only about 15-30%. Their breath rate can be as low as 1 breath every 45 sec vs 6-10 breaths a minute in active season. Their heart rate during the active season can be approximately 40-50 beats per minute vs hibernation season at 8-10bpm. Grizzly bears are a medical marvel when it comes to hibernation. Being virtually still for 4-6 months and losing no bone mass or density is both remarkable and a medical mystery. Muscle mass and tone are kept by a shiver reflex and urea broken down from fat metabolism results in nitrogen which also allows the maintaining of muscle mass and organ tissue. Their cholesterol levels are twice as high during hibernation as it is during their active season, yet they do not suffer from hardening of their arteries or form gallstones. In fact their liver secretes an enzyme that would dissolve gallstones in humans with no need for surgery.

It is amazing to think of Boo while all these processes are taking place within his body. To learn about the fascinating transitions their bodies endure every year is absolutely remarkable. Bears typically go through 5 stages each year even though we have only 4 seasons. Stage 1 being normal hibernation, stage 2 is called a walking hibernation, stage 3 is normal activity, stage 4 is hyperphagia and stage 5 is fall transition. Check out this link for a more detailed description of each of these stages.
http://www.bear.org/website/bear-pages/black-bear/hibernation/191-5-stages-of-activity-and-hibernation.html

Happy Winter Everybody
Nicole Gangnon, Grizzly Bear Refuge Wildlife Ranger

November Refuge Update

The day started with dense fog, visibility virtually impossible. Ross and I discussed the possibility of confining Boo to his wintering yard, noting how well he’d been entering for supplemental feedings over the past week. The decision is to play it by ear. Once we arrive at the habitat and observe Boo’s rate of movement and behavior we will decide if it’s the right time. As we arrived at the refuge at 10:30am, Boo was out of sight. Ross decides it would be best he do the perimeter check, calling Boo while moving around the habitat. Boo has typically appeared on the west side of his habitat to greet Ross over the past few days, following to the North West Corner before plunking his bum down to observe Ross continue down the north fence line.
Ross meets me back at the truck to discuss plan of action and he decides we should give it a go but this year I am to remain in the truck, unseen and unheard to avoid peeking Boo’s suspicions. Ross takes Boo’s supplements and once Boo see’s his food bucket he decides to descend the north fence very slowly, pausing to take information off the northern winds before reaching the west habitat gate. Ross has ingeniously devised a trip rope for the gate, allowing me to remain hidden and Ross to remain on the den roof to calmly talk Boo through the gate. Boo hesitates at the west gate, and Ross toss’s Boo a piece of raw pork to entice his tummy for more. Ross spreads the remainder of Boo’s supplements into his wintering yard and by 11:30am Boo was safely confined. He is never impressed with us after this event but he is quick to realize it’s all for the best and Boo is always given rewards for being cooperative. It didn’t take long for Boo to resume foraging the grapes and sunflower seeds he loves so much.
Boo is not hibernating yet. The snow is just not here to stay as our temperatures have been rather mild. Boo each day becomes less interested in food and soon we suspect he will start to eat roughage such as twigs and bark to form his fecal plug before entering his den. Once Boo has spent 24hrs inside his den, he will be deemed in hibernation. Monitoring for the winter will be limited to a recording device located in the den roof which allows us remote glimpses into the hibernating world of Boo. These images and videos will be shared with all of you throughout the winter here on Boo’s page. So keep checking for more updates and personal posts by Boo.
Thanks again for your continued support and interest in Boo
Have a safe and happy winter season

Nicole Gangnon, Grizzly Bear Refuge Wildlife Ranger