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Jeanie through summer — habituation, pregnancy and delayed implantation Black Bear Researcher Ripping sounds were all around me… coming closer and closer… yet I felt nothing.
Jeanie through summer — habituation, pregnancy and delayed implantation

Black Bear Researcher

Ripping sounds were all around me… coming closer and closer… yet I felt nothing. In the world between consciousness and sleep, I was so disoriented fighting to discern if the sounds were real and threatening or components of a dream brought on by endless bear encounters.

I had been hiking all day on Whistler Mountain finding and following nine different bears. The tears and rips were louder now – very close and distinct, but what? I struggled to gain composure. I could see sky, clouds, and bands of green. Then I felt pain. I slammed my right hand into the side of my face and shot up and out of my involuntary stupor. I sat up wobbly, in shin-deep clover. I looked down at my right hand, blood smeared across the tips of the index and middle fingers – big bad mosquito. This tiny but resilient pest shook me from hardened sleep.

I must have dozed off, or more likely passed out after pausing along the crest of a steep ski slope. I can see why I chose to stop – nice bed, red and white clover stems flourished nearly 40-cm high.

Being jolted out of sleep hurts; reminds me of a high school afternoon social studies class when being discovered dozing resulted in severe consequences.

My head ached. But what of the ripping sounds, a dream? The bear attack dream? Don't get too many of those anymore.

I sat up, looking down the lush, undulating ski trail. It was getting dark. The wind was cool and invigorating, slowly bringing me back to life. I glanced toward the east and was met by the largest full moon I had ever seen. It loomed over Fitzsimmons Glacier like a… ripping sounds again. I peered through shadows over my left shoulder and less than 4 metres away, a pair of large brown shoulders, almost entirely camouflaged by a dense canopy of clover, worked back and forth as a familiar bear’s head bobbed up and down. Each bob was followed by the short, but pronounced ripping of vegetation. I smiled at the sounds of the clover being torn from their stems. Jeanie was sprawled on her belly, fore- and hind-paws outstretched. Her head worked the area between her massive forelegs and paws. Her four canines grasped fist-size clumps of clover ripping the leaflets from their erect stems. She took three more bites of the loonie-size Trifolium leaflets before glancing my way. She chewed vigorously, not quite as effectively as a cow or deer but indeed, the stems and leaflets disappeared quickly behind the large canines.

During the last seven years Jeanie and I have developed an understanding communicated through body language and vocalization. Jeanie tolerates my presence during hundreds of progressively close observations because each encounter has remained non-intrusive, non-threatening, and respectful of not interrupting her natural food foraging activities. I have never intentionally approached her to less than 10 metres (35 feet) – there is absolutely no reason for it. Her reward is the access to concentrated, enhanced natural food – lush clover, protein-rich carpenter ants, and sugary berries. All consumed, in the presence of a human, a situation that would undoubtedly send most bears running.

Bear biology revolves around food and female bears, whether pregnant or with COY (cubs-of-the-year), require most of it. Jeanie habituates to my presence to benefit from food availability, rather than running from me and losing the opportunity. Bears exemplify learning and memory. Having the largest brain mass relative to body size of all the carnivores provides them with heightened senses, allowing them the ability to distinguish and recognize individual people from numerous encounters.

I do not feed bears and getting close to observe them is only a research tool that is strictly employed based on their reactions. Close observations of Jeanie and other female bears has allowed me to experience the black bear’s world of maternal caring, risk, loss, adaptation, and biological dynamics so intriguing that my own life cyclic events follows the temporal pattern of theirs.

It’s late June and Jeanie’s two-week estrous period has ended. During the first three weeks of June she courted and mated with a minimum of three different males. Adult female black bears sexually mature at 3.5-5.5 years or possibly longer depending on individual condition reflective of genetics and habitat quality. Breeding occurs from late May through late July. No courtship or copulatory activity (in bears that is) has ever been observed in August.

Bears are induced ovulators meaning females require the physical act of breeding to stimulate the release of eggs. Sperm and egg join to form a zygote. This single-celled zygote enters the oviduct and develops into a hollow ball of cells (as it travels to the uterus) called a blastocyst. During early August the bear’s 220-day gestation period is interrupted by delayed implantation. For 120 days the blastocyst free-floats and delays from implanting into the uterine wall. This four-month period (August-November) coincides with huckleberry feeding. Huckleberries are the key seasonal food for bears in Whistler, allowing sufficient weight gain to build winter fat reserves.

Pregnant females follow a 2-3-7 cycle of approximately two months of green vegetation grazing, three months of insect and berry feeding, and seven months of hibernation, including cub rearing. August and September are the most important months for weight gain while bear’s scramble through 22-hour days feeding on huckleberries.

During early December after being in the den for one-three weeks (den entrance begins in early November), the blastocyst reacts to weight gain and either implants within the uterine wall or fails due to insufficient nurturing resources. Upon implantation, fetal development is rapid, within six-10 weeks. Jeanie’s success in giving birth to cubs in January 2002 will depend on the production of the high elevation (> 1,200 metres) huckleberries during August and September.

The forecast so far looks good, with about 60 per cent abundance at berry plots. Huckleberries are ripe in the valley and are in the green, fruit swell stage throughout the large huckleberry shrubfields on Whistler Mountain. A sunny August with days of intermittent rain and slightly cooler temperatures will produce a good berry crop for the bears.

Bear Update columns are sponsored by Pique Newsmagazine. Questions or information about black bears call me at (604) 898-2713.




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