Group Dynamics of Yellowstone Pronghorn

The American pronghorn in the Yellowstone region have proven to be gregarious animals. Observations of group dynamics have found their interactions to be influenced by social, reproductive, and environmental factors. Pronghorn were also found to be somewhat unpredictable, making it more challenging to develop conservation strategies for this species. A study published in the Journal of Mammalogy reported about tracking the locations of 53 adult female pronghorn fitted with VHF and GPS radio collars in Yellowstone National Park for nearly 6 years. The Yellowstone population of pronghorn is a native species of special concern. They number fewer than 300, and are one of only a few pronghorn migrations remaining in the greater Yellowstone region. Observing changes in how animals behave as groups can give clues to the influence of environmental and human factors on their survival. The American pronghorn displays flexibility in behaviors of grouping and mating that could indicate resilience to changes in the environment, but this flexibility can make it difficult to create management strategies for the population. Grouping patterns of pronghorn change due to availability of food, density and demographic variables within the group, and human factors such as fencing and hunting. In this study, females switched groups frequently, and groups became smaller when females were giving birth and rearing their young. Snow pack and the number of predators also affected group sizes and cohesion, but habitat and vegetation had less influence. Examination of Yellowstone pronghorn found that they favor lower elevations during the winter, avoiding deep snow. Building on this information, the National Park Service has undertaken restoration efforts to ensure that native vegetation and migration routes to these favored areas are re-established. Conservation efforts seek to control disease, protect or restore key habitat, regulate harvests, and limit adverse effects of development and recreation. When planning the timing and location for conservation actions, biologists must consider what this grouping behavior can reveal about the species. Full text of “Group Dynamics of Yellowstone Pronghorn,” Journal of Mammalogy, Vol. 93, No. 4, 2012, is available at http://asmjournals.org/.