The Relationship Between Wolves and Deer

Mar 15, 2018

How do you feel when you think about a wolf killing and eating a deer? Or perhaps you haven’t given it much thought before now?

In this week's episode of Wildlife Matters, the Masked Biologist examines the predator prey relationship of wolves and deer.

From time to time I receive an account from a reliable source about what I assume was a well-meaning sportsman who interrupted a wolf that was in the process of killing a deer. Sometimes people find a partially eaten carcass and remove it, other times they get involved while the kill is occurring. I hear about people purposely interacting with wolves because they are concerned about the well-being of people, livestock, and pets, too. While I can’t tell anyone what they can or cannot do, I recommend anyone who is considering interacting with a wolf on the hunt consider a few points.

First, I want everyone to be safe. Wolf attacks on humans are historically uncommon, but they have been increasing. In a study by Mark McNay, he examined wolf-human interactions in North America. For much of the last century, wolf attacks on humans were rare, but apparently the increase in wolves over the last few decades has increased the incidence of wolf-human interactions. It appears that habituating wolves to humans contributed to 11 unprovoked attacks since 1970, with 7 more attacks coming from seemingly unhabituated wolves. These attacks occurred across Canada and Alaska; it is important to note that Wisconsin has not had a single incident of this type documented in the last 40 years. This is unprovoked attacks, though, and if you interrupt a hunting or eating animal, I would definitely consider it provocation. Wolves are wild animals, and in the act of hunting and killing prey, they could be expected to be even more aggressive and unpredictable than usual. It is a lot of work to kill prey, and predators are operating on instinct at that time. The blood in their bodies is concentrated in their muscles and vital organs so they can complete their task. This means the part of their brain that assesses risks and rewards, decision making as it were, is lower priority and is not in control. There is no logic, no reasoning – only instinct and muscle control. Also, the body generates hormones like adrenaline to give it extra strength, endurance, and sensory function, which can also make them more agitated and aggressive.

Second, wolves are apex or keystone predators performing a crucial function in the ecosystem. Studies have shown that wolves will “test” several potential prey animals before taking one down for the kill. For the wolf, this is a way of saving its energy and taking the prey that gives it the most benefit for the least cost. Granted, in a winter more severe than this one, they may not test ten or twelve animals—it may not take much testing at all to find a vulnerable animal. However, generally, we would expect that wolves are killing deer that cannot evade a predator because they have some kind of defect that makes them easier to catch. It might be injury, or illness, starvation, or even age-related weakness. Even in the mildest winters, we know at least 1 out of 10 deer dies from one of those ailments, and death by freezing or starving is very slow and painful. Predation reduces that suffering, and the carcass is consumed strictly for survival. The deer that evade and survive predation are the most fit—smart, tough, wary and wild.

Finally, it is important to understand the role that deer play in the wild. We humans, we passionate outdoors enthusiasts, hunters, or non-consumptive wildlife watchers, have an innate fondness for deer, and feel a need to protect and care for them. We consider them our own. We don’t like to see deer suffer. We don’t like it when they starve, or look hungry, or struggle with injury or disease. It is not much of a stretch to say we don’t like to think of them getting killed and eaten by predators. Deer are a part of the natural order of things, though, and supply important food for many carnivores and omnivores, including man. Many birds will feed on deer, from chickadees to bald eagles. All sorts of mammals feed on deer carcasses too. I even heard a first-hand account of a wood turtle scraping meat off the rib cage of a deer. Prey species are animals or birds that get consumed by predators, and it is a description that fits the majority of birds and animals in Wisconsin. Deer are majestic, beautiful, mysterious animals, but they are also a delicious prey species, and as such our Northwoods ecosystem relies heavily on their contribution.

Striving to make new things familiar and familiar things new, this is the Masked Biologist coming to you from the heart of Wisconsin’s great Northwoods.