Learning how moose behavior may have been altered by humanity´s century-old experiment of removing predators
- Steve Mirsky
- Jun 01, 1997
If you can't beat em, join em. That was the conclusion wildlife biologist Joel Berger came to before starting last winter's fieldwork, studying moose--Alces alces--in Wyoming's Grand Teton National Park and in parts of Alaska.
Along with wife and colleague Carol Cunningham, Berger is interested in learning how moose behavior may have been altered by humanity's century-old experiment of removing grizzlies, wolves and other predators from the big ungulates' habitat. "Our research is concerned with what happens to prey in systems where large carnivores are absent," Berger explains. "We feel this is an important issue because in most of the world more systems are going to be losing large carnivores, rather than gaining them. What are the direct consequences of such losses?"
In the course of doing this research, Berger realized that the only way to get some of the information he was looking for was to perform a variation of the old "wolf in sheep's clothing" routine. He decided to become a "scientist in moose clothing."
A University of Nevada wildlife biologist, Berger has spent the last two decades studying different large mammals, including rhinos in Namibia and wild horses in the American Southwest. In addition to moose, he now studies elk and bison. Why only large mammals? "It's hard to watch bats and it's hard to watch rats," says Dr. Berger, sounding more like Dr. Seuss. (He grouses at mouses, but loves Alces alces.)
Berger's comparison of moose behavior in Grand Teton, where predators are rare, and in Alaska, where grizzlies and wolves are more common, has already revealed some marked differences. For one thing, moose in Alaska remain quite sensitive to recordings of the sounds of predators, becoming alert and reducing the time they spend feeding. In the greater Yellowstone area, however, moose seem unconcerned when they hear the same tapes, indicating a fundamental behavioral change because of their human-altered environment.
Berger also wanted to study behavioral changes associated with the animals' sense of smell, since moose rely heavily on their olfactory abilities. To test the creatures' reactions, Berger uses a potent source of predator aroma: dung.
Finding predator waste is easy enough, but depositing it close enough to moose to systematically observe their reactions is a messier issue. Moose get a bit skittish when humans approach, so Berger ("I had played some ball in college") first tried lobbing wolf and bear scat at moose, but he failed to muster the kind of distance he really needed. He then tried slingshots. "But they don't work so well," he admits, noting that the lack of structural integrity of the average dung sample led to some unfortunate scattering when pinpoint accuracy was in order.
Finally, Berger hit upon the "stealth" approach to dung depositing. He was aware of a wildlife photographer who wore a zebra skin like a pancho to wander among herds in Africa. He had also seen paintings of Native Americans wearing wolf heads and capes to sneak up on bison. He thus enlisted Debra Markert, who had been a designer for the Star Wars movies, to create a moose suit.
Moose don't mind each other's company, especially in winter when they cluster at food sources. The plan, then, was that he and Cunningham would don the suit, saunter up to their study subjects to drop some research dung, observe the reaction, and get out of there without disturbing the moose. (Berger and Cunningham actually live in Moose, Wyoming, so masquerading as a moose in Wyoming is only a bit of a stretch.)
I thought he was kind of loony to be considering it, to be frank, until I saw the suit in action," recalls Steve Cain, the senior wildlife biologist for Grand Teton National Park. "It became clear that the thing might actually have some utility, that it would probably let him approach moose closer than he would be able to on foot."
A big part of the success of the suit, according to Cain, is that Berger and Cunningham do a pretty good moose impression. "They've got their movement to mimic that of a feeding moose," he notes, "one that's calm and basically going about its business. So I don't think the costume drew as much attention, or perhaps fright, from other moose as it would have had less experienced people been in it."
Even given their talent for mimicry, traipsing around in the moose suit can be a risky enterprise. A large moose in the lower 48 states weighs as much as 1,000 pounds, so getting charged by one would be highly dangerous.
Berger carries a whistle and pepper spray, but he found a far better defense when a moose suddenly took umbrage last winter as he and Cunningham came too close. "Carol and I were in deep snow and a moose lowered its ears, dropped its head and the hair on its nape stood up," Berger recalls. "Think of a dog, when it gets nervous and its hackles stand up. That's basically what a moose does. And we were only about 15 yards away from it. And because we were in deep snow, it was like, uh oh. So we took the suit off. And the moose was very confused. Its demeanor changed. We went in opposite directions."
Berger and Cunningham got into the moose suit about 20 times this past winter, for the half-hour or so that it takes to accomplish the dung dump. Most of the time, they behaved more like conventional field biologists, watching their animals from a safer distance. "You need to remember that the moose suit is getting all the press," Cain says, "but that's a real small aspect to everything else that Berger's doing."
Still, the suit is noteworthy for a number of reasons, besides being a unique tool useful for solving a specific problem. Many researchers have a reputation for relying on students and technicians to do fieldwork, while they go over their team's reports back in their offices. Berger insists on getting into the action himself, to get a truer feel for how his study animals behave. His willingness to literally immerse himself in his moose is merely an extension of that attitude.
Next winter, Berger will again attempt to approach moose, while trying to put more distance between himself and park visitors. "The typical tourist response when they see us," Berger says, "is they just roar and they want to get pictures. Meanwhile, we're trying to do our work. But we have to try to explain what we're doing and be polite, so we lose a lot of time. For us, it makes a lot more sense just to avoid roads." Clearly, some scientists must go to great lengths to get into the animals they study.