Moose-mating season, just around the corner in Alaska, means crisp fall days, ripe berries on the bushes and, according to a new study, animal behavior that might seem more at home in a rowdy singles bar.
Female moose, or cows, are able to manipulate amorous males into fighting each other, allowing the more desirable bulls to emerge as mates, according to the study, which is based on observations made in Alaska's Denali National Park.
The cows' efforts are subtle, so they have long been overshadowed by the belligerent, antler-clashing behavior of bull moose in rutting season, said the study, which published by the academic journal Behavioral Ecology and Sociobiology.
"Because we have so much aggression in the big males, it actually masks female choice," said Terry Bowyer, a biologist at Idaho State University and one of the study's authors.
Female moose use protest moans to ward off small male suitors, the study points out.
Bowyer and his study partners found they also use those protest moans when approached by some big suitors, setting off fights between large bull moose.
The biologists spent four autumns tracking and observing moose in Denali, listening to grunts and moans and recording behavior, including fights. They concluded that the females actually foment male-male aggression.
"It's indirect control," Bowyer said. "They're manipulating a mating system in which you think they didn't really have choice."
Finding the right mate at the right time is critical for successful reproduction, the study points out, because of the "extremely synchronized manner" in which cows give birth in May and a restricted growing season, which limits young moose's opportunities to eat enough food to survive the harsh winters.