Post by brobear on Mar 26, 2017 23:59:49 GMT -5
The grizzly is a predator of both black bear species.
From Frank321 to BigBonns...
BigBonns,
There has been more than one instance; to my knowledge they have occured in Hayden Valley, Hoodoo Creek, and Grizzly Overlook. Here is one study that conducted an autopsy on the black bear:
www.greateryellowstonescience.org/files/pdf/ys5-gunther.pdf
I'd also like to make a few comments on grizzly-black bear interaction. In general, both brown and black bears are K-selected species. Black bears evolved differently from their brown cousins in forested areas. These forests that blackies live in allow them to escape predation from grizzlies relatively easily; a boar black bear at about 55% the size of a boar grizzly can climb to much higher branches.Grizzlies on the other hand tend to live in rockier regions and open grasslands. In these areas bears can find food through fossorital behavior or under boulders and rocks. It's when black bears wander too far away from forests that they risk predation from grizzlies. Lacking the shoulder hump of brown bears, they can't power their limbs to move as rapidly as grizzlies and as a result aren't nearly as fast, with black bears moving at about 25-30 mph and grizzlies at over 30 mph (in at least two cases brown bears have been recorded at 40 mph, although in one the bear was a sow and presumably quite light relative to a boar and in another of unconfirmed gender). The foraging behaviors of black bears may lead them out of forests, as a note. For example in spring black bears emerging from their winter hibernation will sniff out newborn elk calves in fields of grass which are outside of their forest biomes. During mating seasons, and because of the competition associated with Darwinian fitness, young boar grizzlies may also be driven into forests temporarily where they may encounter black bears. The case at Hoodoo Creek may be one such case, although I haven't looked into it too much.
Here's moreinformation on the case of the Hayden Valley predation as well:
www.nps.gov/yell/naturescience/upload/predation.pdf
From Frank321 to BigBonns...
BigBonns,
There has been more than one instance; to my knowledge they have occured in Hayden Valley, Hoodoo Creek, and Grizzly Overlook. Here is one study that conducted an autopsy on the black bear:
www.greateryellowstonescience.org/files/pdf/ys5-gunther.pdf
I'd also like to make a few comments on grizzly-black bear interaction. In general, both brown and black bears are K-selected species. Black bears evolved differently from their brown cousins in forested areas. These forests that blackies live in allow them to escape predation from grizzlies relatively easily; a boar black bear at about 55% the size of a boar grizzly can climb to much higher branches.Grizzlies on the other hand tend to live in rockier regions and open grasslands. In these areas bears can find food through fossorital behavior or under boulders and rocks. It's when black bears wander too far away from forests that they risk predation from grizzlies. Lacking the shoulder hump of brown bears, they can't power their limbs to move as rapidly as grizzlies and as a result aren't nearly as fast, with black bears moving at about 25-30 mph and grizzlies at over 30 mph (in at least two cases brown bears have been recorded at 40 mph, although in one the bear was a sow and presumably quite light relative to a boar and in another of unconfirmed gender). The foraging behaviors of black bears may lead them out of forests, as a note. For example in spring black bears emerging from their winter hibernation will sniff out newborn elk calves in fields of grass which are outside of their forest biomes. During mating seasons, and because of the competition associated with Darwinian fitness, young boar grizzlies may also be driven into forests temporarily where they may encounter black bears. The case at Hoodoo Creek may be one such case, although I haven't looked into it too much.
Here's moreinformation on the case of the Hayden Valley predation as well:
www.nps.gov/yell/naturescience/upload/predation.pdf