Moose on the Loose

One of Jackson Hole’s most iconic large ungulates, moose, only showed up in the Greater Yellowstone Ecosystem about a century ago. At first, they thrived, but then the population crashed. It still hasn’t come back.

// By Mike Koshmrl

Sometimes they barrel out of the timber and tear down the slopes, sending skiers scampering for safety. On other occasions, they’re holding up traffic, maybe even near the Jackson Town Square. Or perhaps one decides to make its bed right in your backyard. They’re massive, about six feet from hoof to shoulder and weighing up to 1,000 pounds. Although lumbering in appearance, they can run as fast as 35 miles an hour, so don’t get too close. (Don’t think water will keep you safe, either; they can swim up to six miles an hour for up to two hours at a stretch.) While not normally aggressive, they will charge if stressed or agitated, and these attacks can be deadly. Although they haven’t killed any humans in Jackson Hole, they’ve injured plenty. Humans inflict a more significant toll on these animals that share our environment, killing about 30 of them annually on the highways in and around the valley.

The species? Moose.

Alces alces, the largest member of the deer family on the planet, has long captured the fascination of residents and visitors to the Greater Yellowstone Ecosystem, dating back to when they first arrived. It wasn’t that long ago, relatively. There is zero archaeological evidence of moose being in Wyoming before the 1800s, according to the Wyoming Game & Fish Department.

Generally, moose are a species of the far north’s boreal forest. Their native range stretches from the western tip of the Alaska Peninsula clear across North America. They’re found across Eurasia, too, all the way from Scandinavia into western Russia and into Siberia. The exact extent of moose range at the time Anglo fur traders and homesteaders arrived and occupied the American West is unclear, but indications are that there weren’t many south of the Canadian border. During the 1804–1806 Lewis and Clark expedition, for example, the exploration party documented only a single moose along the group’s route, which traveled through areas where moose are now commonplace. 

While moose were translocated to other areas in the Rocky Mountains—like the Bighorn Mountains in north-central Wyoming (in the 1940s) and Colorado’s North Park region in the 1970s and ’80s—the moose that moved into the GYE did it on their own. “They’re an example of a species naturally expanding into a new area,” says Aly Courtemanch, a wildlife biologist who has been keeping an eye over the Jackson moose herd for nearly a decade. There’s no ironclad explanation for why the Rocky Mountain’s subspecies of moose, known as the Shiras moose, were absent—and why they colonized this ecosystem a little over a century ago. 

There are theories, though. In the early 1900s, large wildfires swept through the GYE, creating a mosaic of younger-aged forests. By the 1930s, wolves, predators of moose and seen as pests by settlers, had been mostly extirpated from the GYE. Simultaneously, grizzly bears, another predator, were hunted down to just a few hundred animals mostly confined to Yellowstone National Park. The grizzly population had declined enough that that species was placed on the Endangered Species List in 1975.

“Moose started at a lower population for a couple of decades, but then the population just exponentially increased. By the mid-1900s, thousands of moose dwelled in Jackson Hole and the mountains ringing the valley.”

—Aly Courtemanch, wildlife biologist

These conditions were like an invitation to moose living north of the GYE to wander south into the mountain ranges and valleys in and around Jackson Hole. “For instance, when moose first showed up on the Wind River Reservation—I think that was in the 1920s—one of the tribal members wasn’t sure what it was, because he had never seen a moose before,” says Joel Berger, a longtime scientist with the Wildlife Conservation Society who studied Jackson Hole moose in the early 2000s. “They moved into the Winds [a mountain range to the south and east of Jackson Hole], they moved into the Wyoming Range [south of Jackson Hole] on their own.”

The same conditions that brought moose to the region helped the population take off. “They started at a lower population for a couple of decades, but then the population just exponentially increased,” Courtemanch says. By the mid-1900s, thousands of moose dwelled in Jackson Hole and the mountains ringing the valley: the Tetons, Gros Ventres, Absarokas, and the Snake River and Wyoming Ranges. “Biologists at that time were counting over 1,000 moose during their winter surveys,” Courtemanch says. “And they were estimating [a population] of two to three times that.” Nowadays, elk hunting makes for routine banter come every September in Jackson Hole. Back up half a century, and the same could be said of the moose—hundreds of moose-hunting licenses were available locally.

The glory days of being a moose in Jackson Hole started sputtering by the end of the 20th century. The populations of predators grew, winter forage was reeling from decades of over-browsing, and the climate started heating up.

In 1995 and ’96, the U.S. Fish and Wildlife Service reintroduced wolves to the Greater Yellowstone Ecosystem and central Idaho wilderness areas. These animals—a total of 66 were reintroduced over the two years—thrived and resumed their natural role, preying on and eating moose. By the turn of the century, there were nearly 1,000 wolves in the GYE and wilderness complexes to the west in Idaho; the large carnivores quickly saturated the good habitat in Jackson Hole. Grizzly bears bounced back, too, with 1,000-plus animals radiating out throughout the ecosystem in recent years.

The highways and roads that conveniently tie Jackson Hole together for its human inhabitants are especiallymalignant to moose. In some years, as many as 30 moose get hit and killed in the valley.

While predator populations were growing, the complexes of willow that moose rely on to survive the winters had been over-browsed by moose themselves and also by over-inflated elk herds and cattle that remained in the GYE’s valleys. “Willows in the ’80s and ’90s looked a lot different than they do today,” Courtemanch says. “They looked almost like a garden hedge; any annual growth was just gone because there were so many animals trying to eat those plants.”

In yet another blow, the climate started heating up. Moose, which evolved in northern climates and mountains, are simply unable to cope well with warm temperatures. In the winter, when their coats fill out, anything warmer than 23 degrees Fahrenheit is stressful to the species. Come summer, the threshold is 59 degrees. Warmer falls and springs have also increased the abundance of ticks, a parasite that sucks the blood of moose and can number in the thousands on a single animal. “A lot of things affecting moose are out of our control: climate change, parasites, and large-scale habitat changes,” Courtemanch says.

But there were also human-related changes. Homes and other development displaced more and more habitat, especially in the river bottoms and riparian areas where moose like to dwell. Between the moose population heyday in the 1980s and today, the human population in Teton County nearly tripled. The highways and roads that conveniently tie the valley together for its human inhabitants were especially malignant to moose. “In some years, as many as 30 moose are getting hit and killed in Teton County,” Courtemanch says. Of course, highways in Teton County have always claimed the lives of moose—even before traffic numbers exploded. But nowadays the toll that vehicular collisions take is especially impactful. “When we’re only counting 300 moose total, 30 moose is a lot,” Courtemanch says.

Today, moose aren’t necessarily in danger of disappearing from Jackson Hole—the numbers are mostly stable—but the population is a shell of what it was. It is now about 80 percent smaller than it was at its peak in 1988, when biologists counted nearly 1,200 moose in their aerial surveys. Although numbers have mostly flattened, Courtemanch says there’s been little sign of recovery. Plenty of calves are being born, but their survival rates aren’t high enough for the population to increase. Although the Wyoming Game & Fish Department has a historical herd goal of 800 animals that dates to when numbers were much higher, that’s essentially an aspirational objective that is no longer achievable. “We’re not going to reach that anytime soon,” Courtemanch says. Over the last three years, the state agency’s surveys have tallied an average of just 275 moose. (Notably, Jackson Hole isn’t the only portion of the United States where moose have struggled. Numbers have cratered in Minnesota. In other places like Maine and Colorado, however, populations have fared much better.)

While the population has stabilized, albeit at a much lower number, the individuals that make up the Jackson moose herd aren’t necessarily thriving. Courtemanch, who’s partaken in necropsies of animals that turn up dead, has encountered plenty of animals in residential areas that “aren’t doing very well,” she says. “We see quite a lot of moose dying. The moose closer to town, those are the ones with [high abundances of ticks].” 

There are some causes for hope. Moose collisions on highways around the valley have generated a lot of attention, and in 2012 the Wyoming Department of Transportation reduced the nighttime speed limit on Highway 390, also known as Teton Village Road, in direct response to five moose that were hit and killed the previous winter. At the location of one of the worst problem areas, near the intersection of Highway 22 and Teton Village Road, there’s also infrastructure intended to reduce collisions in the works. The solution—a network of underpasses—was part of a road reconfiguration and bridge replacement that overall cost north of $60 million (obviously the underpasses are just a fraction of this). During the planning and design period—well before its targeted completion later this year—Courtemanch and her Game & Fish counterparts fit GPS collars onto animals to observe their movement patterns with great precision, and WYDOT located the underpasses accordingly. Hopefully, Courtemanch says, projects like the Highway 22/390 intersection redesign will help the Jackson moose herd turn a corner and begin growing again. 

The population of moose in Jackson Hole today, about 300, is approximately 80 percent of what it was at its peak in 1988, when it was nearly 1,200.

Another research effort being headed by the University of Wyoming could help Courtemanch and others get their arms around where Jackson Hole’s moose go. “A lot of our moose are very migratory,” she says. Moose concentrate heavily along the valley floor in winter, but once the snow melts off, they spread out in almost every direction: north into the Teton Wilderness, east toward the Gros Ventre Range, and south toward the Wyoming Range. Soon, moose will receive GPS collars that inform UW biologists precisely where they head—and then wildlife managers will have new data at their disposal to best conserve moose habitat. 

Another perk of the ecological examination is that it should also help provide some answers about what’s killing moose in northwest Wyoming. Willows in Jackson Hole and surrounding sub-valleys have largely bounced back from the era of intensive over-browsing. And cows have been relatively successful over the last decade at giving birth to calves. Yet, the population has been mostly stagnant—a head-scratcher for some biologists. “One of the questions we’re trying to answer with this new research is, ‘Why isn’t the population increasing?’” Courtemanch says. Regardless of the cause, the moose of Jackson Hole could use a little help. (But not by feeding them—a harmful practice that has persisted even though it’s prohibited by Teton County’s zoning regulations.)

See a moose? Feel free to stop and take a look, but do so responsibly. In Grand Teton National Park, it’s illegal to come within 25 yards of a moose—a viewing threshold that perhaps ought to be abided by everywhere. For humans, it’s a matter of safety. For moose, it’s a matter of survival. “Over the years, I’ve seen too many visitors and locals alike approach too closely,” says Taylor Phillips, a wildlife guide who founded the Jackson-based company Eco Tour Adventures. “For moose—and for all wildlife—it’s important that we give them space and we don’t alter their behavior. We shouldn’t force them to burn extra calories. They need those calories to survive.”

Where can I see a moose?

Moose are one of the more highly sought-after species to see in Jackson Hole, says Taylor Phillips, a veteran wildlife guide and founder of Eco Tour Adventures. The long-legged, dark-brown animals can be denizens of backyards and timber stands, even in the Town of Jackson and developed areas like Teton Village and Wilson, but they’re especially fond of wetlands and areas where willows are found. It’s the reason for one of their nicknames: swamp donkeys. “Willows are a pretty large percentage of their diet in the wintertime,” Wyoming Game & Fish Department biologist Aly Courtemanch says. If you want to try to spot one on your own, Phillips says moose tend to congregate around Antelope Flats and the road to Kelly along the Gros Ventre River. Want help finding moose? There are a host of local wildlife safari companies. Phillips’s Eco Tour Adventures (jhecotouradventures.com) is one of the largest and oldest.

Help count moose

For 15 years, the Jackson Hole Wildlife Foundation has put on its annual Moose Day event—typically the last weekend of February or the first weekend of March. It’s a volunteer-based “citizen-science” survey of moose. “The biggest thing about getting our volunteers out on the ground is that it gets people’s eyeballs on moose that can’t really be seen from a flight,” Jackson Hole Wildlife Foundation executive director Renee Seidler says. “One, the moose might be under vegetation. Two, Game & Fish isn’t really allowed to fly over private lands looking for wildlife.” Moose Day is wildly popular, with volunteer retention near 100 percent. Another Jackson Hole Wildlife Foundation effort, known as Being Wild Jackson Hole, is more geared toward visitors—they head out with a biologist on a trail and count moose together. Questions about either? Visit jhwildlife.org or email Jessie Walters at jessie@jhwildlife.org.JH