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Are We Still Domesticating the Wolf?

Credit: karlumbriaco/Adobe

Credit: karlumbriaco/Adobe

By Thomas Newsome

Modern wolves are being drawn to human sources of food, with serious implications for their evolution and conservation, as well as for ecosystems and humans communities in general.

The grey wolf was the first animal domesticated by humans. The descendants of these wolves walk on leads, herd our sheep and sit on our sofas – they are the dogs we keep as pets today.

The timing of wolf domestication is hotly debated. Some scientists place dog origins around 40–50,000 years ago; others place it around 12–16,000 years ago.

As for where it all began? That’s up for debate too. Proposed locations include the Middle East and other areas in Europe and Asia.

The where and when are yet to be agreed upon, and the “how” is also unclear. One theory is that founder groups of wolves became attracted to food waste on the edge of human settlements. Gradually, these less fearful wolves became separated from the wild populations, and distinct population clusters formed. Once people had direct contact with these wolves, they were kept as pets and/or used as guardian dogs and hunting tools. As time went on, humans began selectively breeding these wolves for desirable traits such as decreased flight behaviour and increased sociality, which are trademarks of tameness today.

Eventually, people established complete control over the mating process and, in effect, the wolf became the dog. There are now one billion domestic dogs on Earth, with a near-global distribution.

But what does historic wolf domestication have to do with wolves that currently roam free on Earth today?

Recent evidence suggests that grey wolves continue to be attracted to food waste and other human-provided foods, akin to the initial stages of wolf domestication. This phenomenon has serious implications for the ecology, evolution and conservation of wolves, as well as for ecosystems and humans more broadly.

To understand why wolf access to human-provided foods is a serious issue that requires an understanding of the relationship between wolves and humans, and an appreciation for their ecological role.

A Short History of the Grey Wolf

Grey wolves had one of the most extensive historical geographic distributions of any mammal, occurring throughout much of the Northern Hemisphere. However, humans eliminated them from much of their former range during the 19th and 20th centuries.

They were eliminated because of the perceived impacts that wolves have on human industries and livelihoods. As a consequence, they became mainly restricted to remote and undeveloped areas with sparse human populations.

However, in recent decades, grey wolf numbers have increased thanks to legal protections, natural recolonisation and reintroductions (such as in Yellowstone National Park). These efforts have led to a groundswell of research assessing the ecological impacts of wolf recovery.

The studies to date have shown that as apex predators, grey wolves can induce top-down forcing that reduces prey abundance, modifies patterns of foraging by herbivores, and suppresses smaller carnivores like coyotes. In doing so there have been documented knock-on effects via multiple pathways, including to plant communities, other carnivores and scavengers, and even to bird communities.

Wolves are now ensconced as a symbol of the wilderness, and this has been a driving force behind efforts to maintain and restore the ecosystem services they can provide. But wolves are also returning to human-modified environments, especially in Europe and some parts of the USA. Little is known about the ecological role of wolves in human-modified environments, but studies to date show they feed on human-provided food such as livestock, livestock carcasses and garbage. In some areas they feed almost exclusively on chickens, goats and garbage. This highlights that grey wolves continue to be attracted to these foods, or are forced to eat them because their wild prey is depleted.

The Issue with Human-Provided Food

There is emerging evidence that predator ecology and behaviour can be dramatically altered when they access and utilise human-provided foods. This practice can alter the relationships between different species, affecting ecological processes and community dynamics.

This means that where human-provided foods are abundant, the ecological effects of wolves will likely differ from those in systems with low or no human presence or effects. Such a possibility has not been fully explored, but case studies on other predators illustrate the diverse ways in which they adapt to human-modified environments, including eating large quantities of anthropogenic foods.

In Australia, for instance, dingoes that eat large quantities of garbage have smaller home-range areas and movements, larger group sizes and altered dietary preferences to the extent that they act just like domestic dogs. Similar responses have been documented for red foxes in Israel and bear populations in North America. Interestingly, studies on dingoes and red foxes reveal that genetically distinct population clusters can form when these species congregate in areas where there are human-provided foods.

Wild predators can also become habituated to humans after prolonged periods of contact. In Western India, for instance, Asiatic lions can apparently be viewed by tourists at a very close distance. Dingoes living around humans and eating mostly garbage can also become playful and even walk within a metre of people without a worry.

While close encounters with large predators might excite some people, it can result in conflict, especially if the predators show aggression towards humans or they cause damage to human industries. This often results in retaliatory killing of predators by humans, impacting on survival rates and contributing towards the anti-predator sentiment that is often associated with species like wolves.

An additional issue is that human-provided food sources can act as a sink for different species to interact with each other. In some cases it may facilitate interbreeding between different species. Grey wolves, for example, can interbreed with domestic dogs and other species like coyotes. This hybridisation poses a threat to the conservation of wolves, and can even result in coyote populations becoming more “wolf-like” because of the infusion of genes affecting body size and skeletal proportions.

Broader Consequences for Wolves and Humans

How do we predict the outcomes for grey wolves when they become heavily reliant on anthropogenic foods? Several viable hypotheses can be derived from the case studies highlighted above.

First, the ecology and behaviour of wolves is likely to be altered. Such effects include changes to group sizes, diets, home ranges and sociality. This would raise questions about the ecological roles of wolves that exhibit such changes.

Second, human–wolf conflicts could lead to greater rates of humans persecuting wolf populations. Thus, the gradient from wildlands to human-dominated landscapes is likely to be characterised by a shift from predominantly non-human to anthropogenic mortality of wolves.

Third, populations of wolves that rely on anthropogenic resources could diverge from other wild populations due to natural selection and genetic drift. This is the same process by which wolves potentially embarked on the pathway to domestication.

Fourth, high rates of interbreeding between wolves and domestic dogs, or wolves and coyotes, could lead to the incorporation of suboptimal genes into wild populations.

Finally, there are likely to be widespread implications for human welfare and conservation policy. Wolves are still hunted in many areas. Opportunities for conflict will increase if close encounters between wolves and humans become more frequent or if wolf predation on pets and livestock increases. Predation on livestock, in particular, can act as a lightning rod for conflict between humans and large predators.

Avoiding Conflict and Future Studies

The best way to avoid these scenarios is to reduce the amount of agricultural and food waste that is available to wolves and other predators, but it also requires that wolves have access to viable habitat and wild prey. This means slowing down the rate at which land is being converted to agriculture. In some instances it might require restoration efforts to repatriate landscapes with wild ungulates – wolves’ main natural prey.

Fortunately, we can easily study the ecology and behaviour of wolves in human-modified environments to determine if their ecology and behaviour is different to wolves in more wild landscapes. In the first instance, this can simply involve collecting wolf faeces to assess what they are eating. If the wolves are showing signs of switching their diet to human-provided foods such as garbage and livestock, it may be an indicator that efforts are needed to provide these wolves with better habitat or more wild prey.

More speculatively, studies assessing the population structure of wolves in human-modified environments could provide insights into the process by which wolves became domesticated. This could help to resolve the ongoing debate about how the wolf was transformed into an animal that is deeply embedded into human society and culture.


Thomas Newsome is a postdoctoral researcher at Deakin University and The University Sydney. The original paper on which this article is based was published in the journal BioScience (https://doi.org/10.1093/biosci/bix022).