It’s the time of year when bears start to think about hibernating—filling up their bellies with the last berries of this year’s not-so-great crop. Although judging by the bear’s steamy traces along our road, they are definitely finding berries somewhere.

I haven’t dissected these stool samples but I’m told they should contain a random mix of crowberry, bearberry, cranberry, and apparently toadflax. They are pretty red though anyway.

Bear tracks show up on the roads, our ATV trails, the sides of the hills, and in the filled-in creeks that only federal bureaucrats can see.

Over here at 37 Mile Creek (45 minutes west of Whitehorse), we definitely have a little wildlife corridor, maybe one of the last in the Whitehorse area, judging by the multiplying subdivisions. Or maybe it’s all the good berry picking spots out here that no one will tell you about. Either way, we definitely have bears.

Last week, my neighbour had to wait on the Alaska Highway for a mother and cub to casually stroll across; such sightings pop up every few days. The evening dog walk now seems more like a hunting safari than a casual stroll.

Speaking of which, the dogs now bark fairly regularly at night—whether this is always a bear or the return of wild horses and radio-collared elk, I can’t be sure. The wolves seem to have already retreated up the valley, so its not them and I don’t think they bark at cougars yet. I’m going to stick with bears.

A persistent bark, a low growl, and some agitated hackles are enough for me to fire off a pen-launcher flare into the pitch black. Better safe than sorry.

For sure, there are a few lone males around, at least one mother and cub, and likely a few more females deciding whether they want to be pregnant or not.

Although they mate in the spring, bears have evolved a safeguard mechanism where the pregnancy will not ‘take’ unless the female is healthy enough to sustain herself and her newborn cub through the winter. I think that is pretty neat.

Called ‘delayed implantation’, the fertilized egg develops to a point and then stalls for most of the summer. If the female has gained sufficient weight before denning for the winter, the egg kicks back into gear. Early in the new year, she will ‘wake up’ enough to give birth and begin raising her cubs, usually two weighing a little over 1 pound each.

Delayed implantation helps not only the female but also the males. By widening the gap between mating and the actual birth, it allows the bears to mate in the spring, and spend the summer fattening up.

When females are putting out the signals, it is pretty easy for the guys to forget to eat, drink, pose for tourists, or focus on anything else. At least a spring fling gives them time to get their head back in the game before prime berry season. Plus, the fact that the embryo could end up fertilized by any one of several different bears leaves them with plausible deniability—a double-bonus.

Dead-beat dads notwithstanding, berry season is a pretty important time of year. With a diet ranging from carrion, to squirrels, to fish, to berries, to almost anything, the whole plan for bears is to gain somewhere around 5lbs a day in peak berry days (up to 400lbs over the season).

Of course, they have to gain this while essentially on the Atkins Diet—not that anyone knows what the Atkins Diet is anymore, now that Oprah is gone.

The 400lb gain is interesting to me because polar bears require that amount of weight to kick-start their pregnancy. Their mating to birthing season roughly reflects that of the grizzlies, however, require only a one-quarter body fat ratio for the egg to gestation to begin. This is more likely around the 100-150lb mark—still enough to loosen the belt though.

Of course, the best thing about delayed implantation is that it allows guides across the North to sound smart when talking about bears to tourists. If you smell a big tip, you might even want to call it by its other name, Embryonic Diapause; that one is a bit tricky because there’s a fine line between tip-worthy knowledge and smarmy pretension.

The mountains are now dusted white and snow clouds lurk in the valleys, but we have a ways to go yet before hibernation. Bears are moving up the hills, but have not settled in for the winter. They still have time to decide they are pregnant or not, I guess.

Kelsey Eliasson is a polar bear guide, artist and essentially unemployable in the real world, which is why he spends most of his time in the north. He also writes a blog about bears at www.polarbearalley.com.