Greater Yellowstone's Grizzlies!

More Grizzly Facts:

• Grizzly bears: Ursus arctos horribilis.
• Size: 350 to 600 pounds, up to 8 feet tall.
• Food: Grizzly bears are omnivores. Most of their diet consists of leafy plants, grass, roots, ants and larvae. They will eat winter-killed big game in the spring. They also eat spawning salmon and cutthroat trout, elk calves, berries and pine nuts. In the fall, they will kill bull elk weakened by the rut.
• Habitat: Mountains and river valleys with few roads and little human activity.
• Behavior: Grizzlies don't breed until they are 3 years old, and cubs remain with their mothers for 1 to 3 years. Their home range is about 400 square miles. They hibernate in the winter and will gain as much as 90 pounds in the fall to prepare for it.
• Bear numbers: About the time of the Lewis and Clark expedition in 1805, there were an estimated 100,000 grizzly bears in the northern Rocky Mountains. In 1975, fewer than 1,000 were known to exist. Today, with protection, the numbers have increased to 1,400 bears.

Close encounters: grizzly advice

To avoid a confrontation with a grizzly, here's what to do:

• The best protection is a sanitary camp: Hang food 10 feet high, store in bear-proof containers or leave it in the trunk of your car. Sleep in a tent away from the food and not in the clothes you cooked in.
• Travel in pairs.
• Be alert, and don't approach bears or animal carcasses.
• Hike in the middle of the day.
• Keep your distance, 300 yards or more, then detour around the bear, getting upwind so it can smell you.
• If the bear is close, within 60 yards, stand your ground. Don't run. If you have pepper spray, get it ready. Slowly back away 300 yards and detour.
• Don't depend on a gun unless you are accurate and fast.
• If standing your ground doesn't work, play dead with hands behind your neck to prevent the bear from turning you over. If the bear goes away, wait a few minutes, look around and leave.
• Don't run and don't climb a tree.

SCIENCE LESSON: White bark pine

The survival of the grizzly bear in the Greater Yellowstone area is directly tied to the survival of the white bark pine, which grows in high mountain areas above 7,800 feet. White bark pine is important because grizzly bears depend on the seeds from this five-needle pine in late summer and early fall when other foods are less available. The bears don't get the pine cones from the trees themselves but by robbing squirrel caches or "middens" in the ground.

This relationship attracts bears away from low country areas where they might run into conflicts with humans. But in years when the white bark pine nut crop fails, as it periodically does, the bears often come into human communities and campgrounds and get into trouble. There also is a connection between the pine and Clark's nutcracker, a bird endemic to the West. The nutcracker collects up to 150 seeds in a pouch under its tongue and then spreads them out in caches of 15 seeds at a time. A single nutcracker could leave seeds in 8,000 caches a season. These caches are often in newly burned areas, which attract the birds because it is easier for them to remember where they left them.

This is the only natural process for reseeding white bark pine. That ties the nutcracker and fire to the grizzly's health. Unfortunately, white bark pine are dying across their range from blister rust, a tree disease introduced into the United States by mistake and by pine beetles. Pine beetles are natural enemies to the white bark pine, but a warmer climate has allowed pine beetles to move higher in elevation and made them a more effective killer of the trees. Scientists like Melissa Jenkins, a silviculturist on the Targhee-Caribou National Forest, are collecting the seeds from blister-rust resistant trees in an effort to develop a restoration program.

"On my forest, we have some of the highest incidents of blister rust in white bark pine in the Greater Yellowstone Ecosystem," Jenkins said.

The loss of white bark pine makes the loss of other grizzly bear habitat to development and other threats even more problematic.