As people learn to live with grizzly bears and wolves that have recolonized areas around southern Yellowstone National Park after a 50-year absence, so too must moose, which apparently have forgotten to recognize predators, according to a study funded by the Bronx Zoo-based Wildlife Conservation Society (WCS).
Published in the Feb. 9th issue of the journal Science, the study shows that moose failed to acknowledge bears and wolves as threats when they encountered them for the first time, leading to initially high levels of predation among these ungulates.
"Just as many of the New World's wildlife suffered high mortality and even extinction upon first contact with colonizing humans, so it appears that moose may not recognize bears and wolves, even though they have only been absent from the study area for 10-15 generations," said WCS researcher Dr. Joel Beger of the University of Nevada, the study's lead author.
Berger and his colleagues looked at moose populations at sites in Yellowstone and Scandanavia, where grizzly bears and wolves have only recently returned, and compared them to populations in Alaska, where predators never left. The scientists exposed the moose to predator "cues," which included recordings of wolf howls and coyote calls, as well as the scents of both grizzlies and wolves. To gather data, the researchers capitalized on unique methods, some of which included the use of human urine as a control substance, and occasional reliance on a moose suit to approach their subjects.
In predator-free areas, moose were six times less likely to recognize these carnivore cues than in Alaska, where similar exposure would frequently cause them to stop feeding or adopt an aggressive-defensive posture.
But the scientists say that moose are a quick study when it comes to other animals trying to eat them. For example, the authors found that moose mothers whose calves were killed in the Jackson Hole area, became 5 times more sensitive to wolf
Contact: Stephen Sautner
Wildlife Conservation Society