University of Wyoming\r\n\r\nWYOMING - Driven by the need for food, moose in western Wyoming are less likely to change their behavior to avoid wolves as winter progresses, according to new research by University of Wyoming scientists.\r\n\r\nThe findings, published March 13 in the journal\u00a0Ecology, provide new insights into the interactions of the region\u2019s apex predators and their prey. The results also highlight the complexity of the relationships between wolves and big-game species, making it difficult to reach general conclusions about whether and how fear of wolves has impacted the ecosystem, the researchers say.\r\n\r\n\u201cWe have known for some time that hungry animals will tolerate the presence of predators in order to forage and avoid starvation, and that phenomenon, called the \u2018starvation-predation hypothesis,\u2019 is supported by our research,\u201d says Brendan Oates, now with the Idaho Department of Fish and Game, who conducted the research as a UW graduate student. \u201cIn this case, close proximity of wolves does cause moose to move, but not enough to drive them from their preferred habitats\u2014especially late in the winter.\u201d\r\n\r\nOates is the lead author of the Ecology paper. Coauthors include his UW advisers: Jake Goheen, associate professor in UW\u2019s Department of Zoology and Physiology, and Matt Kauffman, a US Geological Survey researcher based at UW. UW\u2019s Jerod Merkle, assistant professor in the Department of Zoology and Physiology, also was involved with the research, as were agency personnel from the National Park Service and US Fish and Wildlife Service.\r\n\r\n\r\n\r\nThe scientists tracked movements of dozens of GPS-collared moose and wolves in Grand Teton National Park and the Bridger-Teton National Forest over a five-year period, detecting 120 unique encounters among 25 individual moose and six wolf packs. An encounter was defined as when moose and wolves were within about 1,600 yards of each other.\r\n\r\nThey found that movements of moose increased in early winter following encounters with wolves, but only when wolves were within about 550 yards. Even then, the moose didn\u2019t move from their preferred habitat, which is near streams and marshy areas. Late in the winter, when the moose were presumed to be hungrier, there was no change in the movement rates of the animals in response to wolves in the vicinity.\r\n\r\n\u201cThe unwillingness of moose to abandon preferred habitats following encounters with wolves adds further support for the starvation-predation hypothesis,\u201d the researchers wrote.\r\n\r\nIn contrast, previous research has shown that elk\u2014the primary prey of wolves in the region\u2014will move when wolves approach within about 1,000 yards, even during winter. Elk also move from their preferred habitat to avoid wolves. The difference may be explained simply by the fact that moose are larger than elk and are more likely to stand their ground when approached by wolves, the researchers say.\r\n\r\nAdditionally, the nature of moose\u2019s preferred habitat\u2014described as \u201cstructurally complex\u201d\u2014means it could serve as both a good food source and a refuge from wolves.\r\n\r\nStill, it would be inaccurate to say that the presence of wolves doesn\u2019t affect moose movements.\r\n\r\n\u201cAlthough moose may be generally less responsive to predation risk from wolves, our detection of a heightened behavioral response during early winter suggests that anti-predator behavior is dynamic within and among species of ungulates,\u201d the researchers concluded.