It’s called “hyperphagia”
Grizzly bears get a serious case of the “munchies” this time of the year. “Ravenous” is more the word. It is overwhelming and not a matter of personal character, but genetic programming to prepare for the winter hibernation.
News media articles, agency warmings, and word of mouth tells people that the bears are now actively and aggressively, if needed, in a search of food. They spend all day searching and eating with only short rest breaks. If they find enough food, a grizzly bear can gain 30 to 50 pounds a week at this time of year!
From the human standpoint, hyperphagia is not a great problem if it sends the bears into the wilderness sub-alpine and alpine zones to feast on whitebark pine nuts and army cutworm moths, ladybeetles, and other insects that sometimes occur in huge numbers there. The moths and other insects seek the wildflower pollen or eat other insects that have become very abundant.
Unfortunately, abandance of these foods that take the bears far from humans is not reliable. Most people who live in or near the mountains know whitebark pine is not doing well due to pine blister rust, mountain pine beetles, and the growing number of high altitude wildfires.
The periodic disappearce and the more worrisome long term collapse of safe grizzly foods has led to a number of articles worrying about the bears’ future. See, for example, Fate of Yellowstone grizzlies tied to key foods. By Christine Peterson, Casper Star-Tribune.
The federal govvernment’s Fish and Wildlife Service would like to delist the grizzly bear from the threatened species list, but it is the demise of the whitebark pine that has stopped them from doing it. They could not convince a federal judge that the grizzly had enough food in the Greater Yellowstone ecosystem (GYE) because most of the whitebark pine had died or burned, that on top of the demise of the Yellowstone cutthroat trout which had been a fine source of protein for the bears.
The grizzlies are anything but picky eaters, and they can substitute other foods when one or more of their staples disappears. In the case of the disappearing trout, the grizzlies turned to the elk of the GYE; and in recent years the restoration of wolves helped them by making more adult elk available to the bears. The bears had long preyed on elk calves, but calves are small food compared to adult elk which are hard for bears to kill. Instead the grizzlies quickly learned to steal elk carcasses from the wolves, and studies show the theft is successful about 90% of the time.
Just outside Yellowstone Park, grizzlies learned long ago that the sound of a rifle in September through November was like a dinner bell. It meant there were elk carcasses and delicious elk gut piles for the taking. Elk hunters tend not to be happy about the taking. The elk hunt provides grizzlies with a huge source of fat and protein at a critical time. At the same time, every year a number of grizzlies get shot during the hunt and hunters get mauled. The first this year was a hunter in Wolverine Creek, deep in the Teton Wilderness. This was September 12, barely into the Wyoming elk hunt season.
Many of the other substitute foods the bears find, or could find are close to humans. The bears do discover new foods and “the word” about them gets around in the bear population. Many people think of the GYE as natural grizzly country, but it’s not. Yellowstone Park is marginal for the bears, but it was one of the few places the bears could live without being killed by humans as dangerous pests that would clean out an apple orchard, rob and tip over beehives, and eat sheep like popcorn (a sheepherder phrase), or simply act aggressively to people nearby even when eating some food no person cared about.
If grizzlies had free choice to eat whatever they found, their population would grow at the maximum biological rate. They would repopulate America easily. This, however, is fantasy, so too is probably the notion that the bears will always find substitutes for foods they know because of their intelligent omnivorous nature.
Comments
This is one problem I don’t expect we will have here this fall with the huge salmon runs. It’s a good thing because we have a new couple working on West Chichagof who are still fairly nervous around bears – they put up the electric fence around their wall tent a few days ago after the guy stepped out in the dark with his head lamp to answer the call, and was startled by the gleaming eyes of a reclining brown bear a few feet away. The night-time vocalizations emanating from the creek are enough to make you shudder in your sleeping bag, but there’s plenty for all down there now and hopefully will be until they start their winter slumber.
Ralph
The fate of Yellowstone Grizzlies may not be tied only to the food supply. A little research for all, appears there can be other limiting factors.
http://tinyurl.com/plp8xoh
I was referring to the first one, Ecology of Denali…
Rancher Bob,
I turned it into a Tiny URL that downloads the PDF file. That might make it easier for folks to get the document.
Hyperphagia in late summer-early autumn is pronounced in grizzlies , for sure. It is assertively present in virtually every other mammalian specie living in the wild, too. And my housecat that I took in off the street . His weight drops below 10 pounds in summer every year , but by November he’s back up to nearly 12 lbs. with a thick coat. He’s eating like the proverbial feral hog these days.