A 300-pound male grizzly bear was drawn to a pungent deer leg when he lumbered into a green steel trap early one June morning deep in the Rocky Mountain wilderness. He woke a few hours later with a lip tattoo, an ear tag, a GPS radio collar, and a new name: Grizzly Bear 927.
Researchers say information collected from bears like this one hold the key to the species’ future, after nearly half a century on the endangered species list.
Thanks in large part to this data, the federal government now considers Yellowstone grizzlies officially recovered, which means three Western states are free to hold highly regulated hunting seasons for the bear. Wyoming and Idaho are planning grizzly-hunting seasons this fall (September-November).
Whether the solitary carnivores can sustain an annual hunting season is a subject of fierce debate. Set aside the ethical discussion—whether or not people should kill grizzlies for sport—and wildlife managers say the bears’ population can absorb limited hunting. (Related: "Jane Goodall Joins Wyoming Protestors in Buying Up Grizzly Hunt Tickets.")
“Large carnivores are never short of controversy,” says Dan Bjornlie, a large carnivore biologist with the Wyoming Game and Fish Department. “But hunting, as long as it’s maintained within the mortality thresholds, is not a threat.”
Critics disagree. Bear numbers might be greater than they were in the ‘70s, when over-hunting, human expansion and a general effort to eradicate carnivores seen as dangerous to humans and livestock saw the species’ population plummet as low as 136 bears in the wild, but that doesn’t mean they are stable enough to allow for sport hunting, said Bonnie Rice, senior representative of the Sierra Club in the Greater Yellowstone and Northern Rockies Region.
“This population is always going to be vulnerable,” Rice said. “It’s the second-slowest reproducing mammal in North America... It’s a species that can’t take that kind of driving down of the population.”
An “Ultra Conservative” Estimate
Beyond the controversy, most wildlife researchers and conservation groups agree that the Yellowstone grizzly bear’s comeback is a remarkable success story.
Officially, more than 700 bears now live in the Greater Yellowstone Area. Researchers say that estimate is low, and as many as 1,000 may actually wander the remote mountains and valleys.
The population can support hunting because it has reached its carrying capacity in many portions of core habitat, says Frank van Manen, leader of the Interagency Grizzly Bear Study Team, a group of scientists formed by the Department of Interior.
And scientific data like that collected from Bear 927 can help effectively manage a hunt by tracking not only the total number of bears, but also factors that affect how many bears could be sustainably removed from the population by hunting, such as the number of reproducing females and survival rates of their young.
A grizzly bear on the move in Yellowstone National Park.
PHOTOGRAPH BY RONAN DONOVAN, NATIONAL GEOGRAPHIC CREATIVE
Each spring and summer, biologists spend several months capturing bears in and around Yellowstone. Almost all of the bears get GPS or VHF collars to track their movements, survival and reproduction.
The resulting information, combined with confirmed sightings of females with cubs, are fed into a series of formulas used to estimate annual mortalities and the species’ overall population.
“When they came up with ways to estimate it, they wanted to be ultra conservative that there was no way you could overestimate the population,” Bjornlie says. “We’re currently underestimating the population a lot.”
So what will protect bears from dropping to the same numbers they did decades ago?
Multiple safeguards, managers say.
Western states can technically hold hunts if the population estimate is above 600, at which point states begin to receive a small percentage of the extra bears. However, there likely wouldn’t be enough extra bears to hunt until the population reached closer to 674, Bjornlie says.
This year Wyoming voted to allow 10 male bears and one female bear to be potentially killed in what’s called the “demographic monitoring area,” a relatively undeveloped swath of land considered suitable habitat, and 12 male or female bears outside of it. Idaho decided on one male bear tag, while Montana declined to hold a hunt.
Only one hunter can be in the field in Wyoming’s core area at a time. If a female is killed, the hunt ends because it would be difficult for future hunters to tell whether they were aiming at a male or a female.
If a hunter in Idaho kills a female, then that female will be subtracted from the next year’s quota, Bjornlie says.
If the grizzly population drops further, to below 500, they could be placed back on the endangered species list pending a federal review.
Planning for the Unknown
Environmentalists like Rice says those contingencies offer little comfort. The Sierra Club is one of several groups suing the federal government to place bears back on the endangered species list. A judge will decide in late August.
Rice worries about a lack of genetic diversity—Yellowstone’s grizzlies are disconnected from any other bear populations—and shifting food sources. Climate change may be reducing the annual crop of whitebark pine nuts, a favorite grizzly food source.
Researchers from the interagency team say the data shows bears are well equipped to survive those challenges. When whitebark pine cone production drops, for example, bears switch to elk calves or bison, says van Manen. There are enough Yellowstone grizzlies to prevent most inbreeding. And the rising number of fatalities in young bears is largely attributable to the climbing density of adult bears, which are now likely killing cubs.
Whether or not a hunter pulls the trigger in September, researchers like Bjornlie will remain in the field trapping bears like 927, keeping tabs on one of the world’s most-studied bear populations.
Lead Image: A grizzly bear in a field of wildflowers in Yellowstone National Park, Wyoming.
PHOTOGRAPH BY TOM MURPHY