Becoming a Bear
As humans we often take an arrogant anthropocentric perspective of the rest of the world. Some actually believe we are God’s gift to the Earth, perfect in every way, and that the Earth was created for the benefit of man and man alone. This perspective is not only arrogant it is also ignorant of the millions of amazing adaptations that organisms possess. Birds ability to fly, an ant’s incredible strength, and the seemingly indestructible water bear which can be boiled, exposed to high level radiation or the vacuum of space without flinching and just some of the amazing things humans can only dream about. The world is not a source of profit for humans, it is a source of inspiration and wonder. The more we discover about our world the more we realize that we are an integral part of a larger system that has been in motion for billions of years.
The American Black Bear (Ursus americanus) is the only bear found in Minnesota and has haunted my dreams since I was a child. I grew up deathly afraid of bears. My fear has prevented me from sleeping comfortably in a tent until very recently. My fear is mostly unfounded as there have been only a handful of documented black bear attacks in the last several hundred years. I have woken up nose to nose with a juvenile bear and I have had four little cubs strut in front of my tent after scaring away their mother. The psychological impact that bears and other large predators has played in the development of my own perspective and the human perspective of the world is significant. We need things that go bump in the night, we need critters that scare the living daylights out of us. This reminds us of our humanity and our place on this planet. I fear for the day when those animals are restrained to zoos or park reserves or are extinct all together.
The black bear has more to offer than sleepless nights in a tent. Every winter bears all across the Northern Hemisphere den up and sleep through the dead of winter. They do not hibernate in the technical sense as they are still active and move around within their den (tossing and turning). They do not eat, defecate or urinate during their time in the den. Females give birth in January or February and care for their young until they emerge from the den in March or April. The ability of bears to survive six months without eating or excreting anything is nothing short of amazing by itself. now add the fact that bears do not lose any muscle mass or definition during that same time. This makes bears super heroes in their own right. Anyone who has spent time in hospital or has had surgery knows that human muscles atrophy very quickly.
How is then that a bear can crawl into a den in October and emerge in March without losing an ounce of muscle??
To answer that question you have to go right to the source, the bear.
Finding a bear in it’s den is no easy task. This particular den had no visible indication of its presence from the surface. Just three feet down there is a sow bear and her two infant cubs. The first order of business was to tranquilize the sow and gather temperature information from the den. It takes a certain kind of person to go headfirst into a den of a mother bear and her cubs.
The first thing to come out of the den are the cubs (pictures to follow). Then with the help of a rope and the tracking collar the sow is gentle dragged from the den.
This is the first time this bear has seen the light of day in over 5 months. She has had nothing to eat or drink since last October and has already lost nearly a third of her body weight since she entered the den.
The den was excavated by the sow bear the previous fall. It was placed under the root ball of a young oak tree. The interior of the den was lined with dry bark and leaves. I’m 6’5″ and I fit quite comfortably curled up in a ball deep in the den. The smell was musky and a bit like a wet dog, it wasn’t bad but it was a smell that you don’t forget easily.
The moment the sow is removed from the den the race is on to gather as much data as possible before the tranquilizers lose their grip on the already sleepy bear. This particular bear is within the study set of two different organizations. First she is monitored by the DNR to get a better understanding of bear populations in Minnesota and what factors influence population density and health. Second she being study in a collaborative effort between the University of Minnesota and Medtronic to determine how bears are able to maintain muscle mass throughout the winter. This bear was implanted with a passive recording device the previous winter. In a couple of minutes they were able to download a year’s worth of data from that device. The device recorded heart rate, motion and body temperature.
Using a portable ultrasound to look at the bear’s beating heart. You could see the valves of the heart quite clearly on the screen!
The sedated bear has a mask on to prevent damaging her eyes with the sunlight.
The bear had dozens of tests, measurements and other data collected during her short time out of her den. The old radio collar was removed. A laceration caused by the previous collar was cleaned and sutured and new collar was installed (the laceration was caused because she put more than expected weight the previous fall, she is a BIG girl!). Blood samples were taken, and rectal temperature was recorded (94.5F). Teeth wear and gum health were recorded. Body fat and density was recorded, for early March this bear still had a lot of fat!!
Each winter bears shed their foot pads in the den. The top photo is from the right hind foot, you can clearly see the old foot pad on the bottom of the heel. The bottom picture is a front foot with all new pads.
This photo might look like they are trying to suffocate the bear but it is actually a quite interesting piece of research that still has no answers. Bears do not eat or drink in the den yet they still breath. A byproduct of cellular respiration is water. How are bears able to sustain life for six months without dehydrating? Nobody knows!!
This sow had two small cubs, a male and female. Each cub weighed a little more than 5 lbs, just a fraction of their 240lb mother!
The cubs were snugglers! Putting them inside my jacket they simply snuggled in and went to sleep. Their claws were very functional and I still have some scratches on my neck from the feisty little male. As a science minded person I try to look objectively at the world but in this case those little bear were simply adorable.
After all the tests were completed, and just before the mother starting to come around, she was slide gently back into her den and reunited with her cubs. There they will sleep for another month or so until spring has transformed their snowy tomb into a forest full of various food sources.
Before leaving we returned the den to ask close to the way we found it as possible.
The research being performed on these bears and other organisms around the planet is helping us better understand the world we live in, and better understand ourselves. As we plow through the worlds “resources” we are also limiting our understanding of how the natural world functions and operates. This research may one day help us become more like a bear in the sense that a surgery or a long term hospital stay does not mean muscle atrophy and loss. My only hope is that the bears and other large predators still have a continued place to share this great human achievement.