Wolves and coyotes are two distinct canid species inhabiting North America, often sharing overlapping territories. Gray wolves (Canis lupus) are larger apex predators, typically weighing between 70 and 150 pounds, while coyotes (Canis latrans) are smaller, generally ranging from 20 to 50 pounds. Both species are carnivores within their ecosystems, influencing prey populations and maintaining ecological balance. Their overlapping ranges have historically led to interactions influenced by their differing sizes, social structures, and hunting strategies.
Competition and Conflict
Wolves hunt coyotes primarily due to interspecific competition for their shared resources, not for food. This interference competition occurs because both species rely on similar prey, such as deer or elk, and occupy overlapping habitats. Wolves view coyotes as competitors for these resources and space, leading to aggressive encounters.
When wolves kill coyotes, it is usually a result of territorial defense and competitive exclusion. They aim to remove rivals from their hunting grounds, reducing competition for available prey. While wolves may occasionally consume a killed coyote, coyotes are not a primary food source. Studies in areas like Yellowstone National Park show that wolf-caused mortality accounts for a significant portion of overall coyote deaths.
Observing Wolf-Coyote Encounters
Interactions between wolves and coyotes are frequently observed, particularly at ungulate carcass sites where food competition is intense. Wolves typically initiate these encounters and often outnumber coyotes, leading to dominant outcomes for the wolf pack. In Yellowstone National Park, 79% of observed wolf-coyote interactions involved wolves chasing coyotes, with about 7% resulting in a coyote fatality.
Coyotes often respond to wolves by exhibiting avoidance behaviors, such as reducing their activity or shifting spatial use. They may avoid areas with high wolf activity, especially during summer, but show less avoidance or even overlap during winter due to available wolf-killed carcasses. Coyote pack size can influence these interactions; larger coyote groups may sometimes deter solitary wolves, but a wolf pack typically dominates.
Impact on Wildlife Populations
The presence of wolves can significantly influence coyote populations, a phenomenon often called the “wolf effect” or a type of trophic cascade. When wolves are present, they suppress coyote numbers through competitive killing and territorial exclusion. For example, following wolf reintroduction in Yellowstone National Park, coyote populations declined by 39% and by 33% in Grand Teton National Park.
This reduction in coyote populations affects other wildlife. Coyotes are mesopredators, meaning they are mid-sized predators that hunt smaller prey like rodents, rabbits, and fawns. With fewer coyotes, populations of these smaller prey species may increase, demonstrating a cascading effect through the food web. This illustrates the role of apex predators like wolves in structuring ecosystems and influencing the abundance and distribution of other carnivores and their prey.