Answer: Wolves, like all wild carnivores, do not kill for sport. They kill to sustain themselves. Though it is uncommon, “surplus killing” (killing more prey animals than can be immediately consumed) has been observed in many predator species. If given the opportunity to secure future meals, many animals will sometimes do so. It is a survival mechanism. It is this survival tactic that has led to the misplaced notion of “sport killing” arises. It has nothing to do with sport. Only people kill for sport.
Surplus killing occurs when prey is at an unusual disadvantage, offering an opportunity to significantly lower both the risk of injury to the predator and the amount of energy required to kill the prey. It is for this reason that surplus killing by wolves, although rare, occurs more with livestock than it does with wild prey.
Typically, when a pack of wolves kills an elk or a deer, by the time the pack has subdued its prey, the rest of the herd has fled and is no longer in the area. This is not the case with livestock introduced by humans. Unlike their wild cousins, livestock have lost much of their survival instinct. Spending a good amount of their existence fenced in or being herded, their reaction to a predator in their midst is very different from that of wild prey. Calves and yearling cattle, for instance, flee during the chaos of the chase, but once the wolves have made a kill, rather than continuing to move away from danger, they have been known to stand nearby, watching in curiosity, perhaps unable to comprehend the threat and what might happen next. Instead of fleeing, as a wild prey animal would, sheep, when confronted with danger, often run in frantic circles, triggering predatory instinct in wolves and increasing the opportunity for multiple kills.
Wolves are further mischaracterized as killing for sport when people happen upon a dead animal or animals, killed by wolves, but the wolves are no longer present. This leads people to assume that the wolves abandoned their kill and therefore, must have killed for recreation or pleasure. This is far from the reality. The fact is that wolves are easily frightened away from their kill by the approach of human beings, whom they regard as a predator and tend to fear. Wolves may be also chased away by other, larger carnivores, eager to take advantage of an easy meal. So a presumably abandoned carcass is not what it seems. In nature, where the margins of survival are narrow, surplus food is not forgotten. Research shows that wolves return repeatedly, almost always eating the entire carcass.
For wolves, more so than bears and mountain lions, hunting can be very risky work. Unlike the larger, solitary mountain lion that relies on the element of surprise, ambushing and then quickly overpowering its prey, wolves work together as a pack, chasing their prey and wearing it down, looking for vulnerabilities. This is very difficult and dangerous, and they are often fatally wounded while hunting, gored by antlers or horns or kicked by a hoof. 80 to 90% of the time, their efforts to make a kill fail. When they succeed, if any food is left unfinished by wolves, it feeds scavengers or other animals.
Misinterpretation of animal behavior and motives often perpetuate a bad reputation for wolves, but reality does not support the theory that wolves kill for sport.