Sunday, December 6, 2009

Bear Tracks

It's a pretty fair bet that most local bears have entered their winter dens, but it's still possible to see bear tracks in the forest if one looks carefully. Several aspen trees along the Beaver Boardwalk have old scars in their bark made by black bear claws. Let me qualify that - the marks were probably made by black bears. Young grizzly bears can climb trees, but they don't do it a lot. I wouldn't either if I were a grizzly cub with such a powerful Mom to defend me.

Black bears climb trees for lots of reasons. Getting food and escaping danger are probably the most common activities. The method is pretty straightforward. A bear grabs the side of the tree with it's front paws and their longer claws, jams the shorter claws on the hind feet into the bark, and hitches up the tree front to back. Black bears can go both up and down pretty fast - as fast as or faster than human climbers you see in lumberjack competittions.

Bruin claws easily penetrate the relatively soft and smooth aspen bark. Damaged bark darkens as the tree heals from the injury, leaving a permanent record of the claw marks. So why climb aspens? The smooth bark is fairly slippery when compared to other local tree species, as anyone who trys to shin an aspen could tell you. Of course, people don't have nice sharp claws to assist the process.

Every spring hungry black bears climb a lot of aspen trees. They are after the nutritious reproductive catkins that appear very early in spring greenup when there's not much else for a bear to eat. I once flew over a patch of aspens on an early spring evening and saw 5 black bears up in the treetops feasting on catkins. That aspen patch was the only one in the area. It drew bears like a magnet, but only for a very short period of time that I was fortunate to witness.

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