How wolf predation shapes elk antler evolution

Date: September 5, 2018

Source:  The University of Montana

What happens when you mix a biologist who studies beetle horns with scientists who spend their time exploring predator-prey dynamics? You get a better understanding of why elk shed their antlers much later than males of any other North American species.

University of Montana researchers and their partners recently published a study in Nature Ecology and Evolution chronicling an evolutionary tie between wolves and when bull elk shed their antlers.

The authors were UM doctoral candidate Matt Metz, along with UM co-authors Doug Emlen and Mark Hebblewhite, Dan Stahler and Doug Smith of the National Park Service, and Dan MacNulty of Utah State University.

They discovered that wolves in Yellowstone National Park preferentially hunted bulls who already had shed their antlers over those who still had them during late winter. The finding suggests that antlers are used for more than just competing for cows -- that they help deter predators, too -- which could help explain why bulls shed their antlers long after the rut.

"Because wolves often prefer elk in these systems, male elk uniquely keep their antlers for much of the winter," Metz said. "Other species, say moose in our study system, shed their antlers beginning in December. We believe elk evolved to keep their antlers longer than any other North American deer because they use their antlers as an effective deterrent against wolf predation."

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