Outside of being hunted by humans for their fur, the coyotes' biggest predator is wolves. In fact, since being reintroduced to Yellowstone National Park in 1995, wolves have reduced the coyote population by 39 percent, according to studies.
Though wolves sometimes eat coyotes, the two do not have a full predator/prey relationship. Instead, both coyotes and wolves are at the top of their food chain and are in direct competition for prey, even at actual kill sites. Because wolves display cooperation in their pack behavior while coyotes live and hunt alone, the coyote is at a distinct disadvantage when confronted.