King of the Mountain
Why do mountain goats compound the perils of their habitat by pushing each other around?
The icy ledge I was creeping along in Montana's Glacier National Park was narrowing fast, and the half dozen mountain goats up ahead seemed about to run out of room altogether. Just when I figured they had all the climbing challenge any hoofed animal could handle, a flurry of fights broke out. A shove on the rump sent a yearling skidding down a ravine, while an adult female, or nanny, overshot her own charge at a subadult and suddenly ended up clinging to a snowy sliver of stone about 15 feet below where she started. Little did I know that during the seven years I would study these creatures, such cliffhanger dramas would grow to seem almost normal.
What I found, along with other field researchers over the past two decades, is that North America's sole rupicaprid, or goat-antelope, lives in a strikingly aggressive society. Biologist Dale Reed, of the Colorado Division of Wildlife, once placed a full-length mirror near a salt lick on Mount Evans. "You should have seen the goats' reactions," he says. "They would rush at their reflection, stamp and threaten it by shaking their horns. Some would climb all around where the mirror was set up, as if intent on finding that other goat."
In Alberta, biologists Francois Fournier and Marco Festa-Bianchet recently confirmed that an individual mountain goat typically takes part in three to four conflicts per hour, often more--not just during the late autumn rutting season but throughout the year. By comparison, bison, chamois, red deer and feral horses all average less than one tussle per hour, while bighorn sheep will clash once every two or three hours.
Most "fights" between goats involve bluffs and chases rather than pitched battles. However, opponents do stab each other on occasion with their dagger-sharp horns. Reed and other scientists have even seen large goats lift smaller ones and toss them in the air. At least as many goats tumble downhill as a result of battling as fall in ordinary climbing mishaps.
No one knows how many of the animals fall to their deaths. It's common sense that not many knock each other off cliffs, or too few would survive. Still, researchers assume some goats do die from falls--and that such deaths play a role in natural selection for the fittest animals. In thousands of hours of observation, I've never seen fatal falls, and the goats have an amazing ability to find something to cling onto. That doesn't mean they don't get hurt. I've seen a number of goats with broken horns and limps.
Why would a creature that literally lives on the edge to start with have a penchant for dangerous brawling? Climbing around looking for answers carries its own set of risks. Nevertheless, scientists have gradually solved the puzzle of goat aggression, piecing together a fascinating portrait of survival in a sheer-sided environment locked in snow and ice for well over half of each year.
As it turns out, the goats' feistiness tends to make large groups split up and keep herds spread out as a loose association of small bands with fewer than a half dozen members. Such an arrangement makes sense when you consider the steep tilt of the landscape. Cliff ledges do not lend themselves to crowds. More important, small groups can make efficient use of a food supply scattered in hard-to-get-at patches. Larger bands would quickly eat up what is available in any given spot, forcing members to stay on the move under often difficult, snowbound conditions.
Another unusual aspect of this high society is that the orneriest goats are not the billies, or males, but the nannies. Social dominance translates into access to the most desirable portions of a range. Through the cold months, those are cliff ledges partially cleared of snow due to strong winds or a sunny, south-facing exposure. No matter how tough the winter, at least some high-ranking nannies have a chance of finding enough nourishment to produce healthy young when spring finally arrives.
During late May or early June, a pregnant female will leave the herd for a secluded part of a cliff to deliver a single kid, or on rare occasions, twins. From its earliest hours onward, the young goat appears determined to climb anything it can reach. Ignoring the fact that its legs are still too weak and wobbly to even walk very well, the newborn scrambles up nearby ledges and boulders time and again--only to wind up back where it started, sprawled on its chin or side. If the mother lies down, the little mountaineer might snuggle against her, and the two will take turns licking each other's face and ears. The next thing you know, though, the baby is trying to climb the warm, snow-colored slopes of its dozing mom.
A nanny needs whatever rest she can get, for she is busy maneuvering to stay right at her boisterous baby's side most of the day. She generally places herself just downhill, the better to nudge the kid away from perilous drops and block any falls with her legs when it stumbles. You would think the term "offspring" originated with young mountain goats, since almost every time one finally gets to the top of whatever it has been trying to conquer, that's what it does: spring off, even though it is likely to land in a heap again.
There are other reasons, too, for a nanny to stick tight to her infant. Both bald and golden eagles nest high on the mountainsides and occasionally swoop down to snatch kids, despite the fact that the birds can only glide, not flap, while carrying an 8-pound newborn. Mountain lions, coyotes, wolves and bears all stalk goats from time to time as well. Should a carnivore appear, a young kid can instantly take refuge beneath its mother's legs, leaving the hunter facing two formidable black horns.
On the whole, mountain goats are hard to reach and all but impossible to outclimb, and their numbers don't appear to be seriously affected by predation. Nor do herds seem very susceptible to disease epidemics. The real enemies are built right into the towering topography goats inhabit: climbing accidents, rockfalls, avalanches and food shortages brought on by deep snows and long, cold winters.
A final reason nannies pay such keen attention to their offspring is that the kids need protection from other goats, especially subadults, which are prone to harass the youngest group members. A mother is quick to chase off yearlings and two-year-olds that approach too closely. She may show more tolerance toward other nannies' kids. At times, she doesn't have much choice, for the babies seek each other out, joining in king-of-the-mountain games and bumbling imitations of adult fighting and courtship behavior. Large nursery groups form now and then during the summer months when food is plentiful and play is the order of the day.
To see a band of mountain goats spread through a flowerlit alpine meadow like dazzling patches of leftover snow or arrayed against the sky on a rugged crag is one of the great wildlife experiences in North America. But exactly which meadows and crags goats rightfully belong on has become something of a question these days.
Oreamnos americanus arose from an Ice Age rupicaprid that crossed the Bering Land Bridge from Asia, where the goat-antelopes known as goral and serow dwell today. During the last major glacial advance, an ancestral mountain goat lived at least as far south as northern Mexico. But when the great ice sheets receded, so did the goat's range. The modern species is native only from Alaska and the Yukon Territory down to southern Montana and Idaho in the Rockies and to northern Oregon along the coastal mountains.
Nannies show a strong loyalty to the home range where they grew up. Billies wander more widely. Yet they, too, are reluctant to venture very far through forested or gentle terrain, where they become far more vulnerable to predators. That reluctance helps explain why goats apparently never reached some isolated mountain chains near the Rockies and Cascades.
In many areas, from the time of the first Western settlers until as recently as the 1970s, overhunting by subsistence and sport hunters took a toll on native mountain goat populations made accessible by logging and mining roads. One part of the solution has been the setting of hunting quotas. And in another counter measure, goats have been transplanted into a number of new habitats, mainly by wildlife departments hoping to boost the variety of big game. Colorado, Utah and Nevada now host thriving herds. Goats have even been introduced to the Mount Rushmore area of South Dakota's Black Hills, where one may sooner or later end up exploring Teddy Roosevelt's monumental moustache. While sportsmen and wildlife-viewers typically enjoy these additions to high country communities, ecologists wonder about the consequences.
The most bitter debate has focused on the Olympic Peninsula of Washington, where goats from Alaska were released during the 1920s and went on to spread through the heart of what would become Olympic National Park. By the 1970s, the growing goat population threatened certain native plants through trampling and grazing. Goat hooves were also caving in the burrow systems of rare mountain beavers on the subalpine slopes. Charged with protecting native flora and fauna, Park Service officials began trapping and removing goats from the most densely populated sites. Managers looked into dosing the rest with contraceptives or even shooting them outright, but a torrent of criticism from a goat-loving public put further control efforts on hold, and no one seems sure how to resolve the issue.
In Colorado, mountain goats were first transplanted in 1948 to Mount Shavano in the Collegiate Range. The state currently hosts about 1,500 animals in a dozen areas. "We've dug up historical records that prove mountain goats were already here in Colorado when the first white settlers arrived," says Arch Andrews of the Rocky Mountain Goat Foundation, which successfully lobbied the state Wildlife Commission to declare Oreamnos a native species.
Biologists aren't so sure about the accuracy of the old reports and worry about competition with native bighorn sheep as goats continue to spread onto new mountainsides. "Goats are just a lot more aggressive," says Colorado researcher Reed. "Out of 107 interactions that I observed between the two species, the goats were about five times more likely to displace the sheep than vice versa." The newcomers' impact on endemic plants also remains a concern.
Wherever mountain goats find themselves as humans decide the animals' fate, the surefooted creatures will make their way toward the loftiest summits to keep company with the winds and clouds and frost, carrying on a way of life that leaves us two-legged climbers open-mouthed with wonder.
Montana writer Douglas Chadwick studied mountain goats in the 1970s as a research biologist in Montana's Swan Mountains and Glacier National Park. He recently wrote The Company We Keep: America's Endangered Species (National Geographic Society, 1996).