Canis familiaris? Maybe Less Than You Think

We think of them as pets, but the vast majority of the world’s dogs live free-range in the environment. Understanding them could be key to helping urban wildlife thrive.

Story by Brian Owens

Dogs have lived alongside humans for thousands of years as wary scavengers, hunting partners, and close companions. They are so ubiquitous in our lives that most people seldom consider the oddity of their proximity—they’re just part of the scenery, or part of the family. 

But that familiarity obscures the fact that dogs (Canis familiaris) are much more than pets. Dogs are one of the most successful animals on Earth. They thrive in diverse habitats and climates, from densely populated Indian metropolises to rural Chilean villages. Of the world’s billion or so dogs, somewhere around 80 percent are not pets restricted to households, but are what scientists call free-ranging dogs.

These dogs are not strays, because that implies they were once pets. But they’re not entirely feral, either. Free-ranging dogs—that is, most dogs—rely on scavenging or begging for food from humans, though some also hunt for wild prey. They’re most prevalent in warmer climates, like parts of the Indian subcontinent and across Africa, but they also dwell nearly everywhere else in the world that people call home. They tend to have a similar look—medium-sized with a light brown coat—though there are local variations. While free-ranging dogs remain closely related to modern pet dogs, different populations of free-ranging dogs have distinct genetic lineages that can be traced back thousands of years. 

“They might be the only mammal besides humans that has spread around the whole globe,” says Christina Hansen Wheat, who studies dog behavior and evolution at Linköping University in Sweden.

“[Dogs] have adapted to thrive in the human environment, but that doesn’t mean they have turned into little people,” adds Clive Wynne, who studies dog behavior at Arizona State University. “We need to think about these animals as animals,” he says. Because if we do, we could glean crucial insights into how free-ranging dogs shape ecosystems, impact other species, and have adapted to living near us—insights that could teach us how to help other animals cope in human-dominated environments.

While the scientific study of dogs has been growing in recent decades, Wynne says most of it is explicitly anthropomorphic—focusing on the cognitive adaptations that make dogs more human-like. And these studies are performed almost exclusively on pet dogs. Mainstream ecology has largely shied away from learning what free-ranging dogs have to teach us, adds Hansen Wheat. “There’s a bit of a feeling that because they are a domestic species they’re somehow inferior, or not a proper species to study.” 

As the pair of scientists argue in a recent paper, paying closer attention to our furry neighbors would be a good model for looking at how species adapt to climate and anthropogenic change. “But nobody is really doing that,” Hansen Wheat says. 

Among the questions Wynne thinks are worth exploring is what factors affect free-ranging dogs’ expression of parental care, particularly by fathers. He’s also curious about the benefits and costs of solo versus group living, and whether free-ranging dogs can survive without any human support at all (including access to things like garbage dumps to forage in). For him, the biggest question is how can understanding free-ranging dogs help us give better lives to pet dogs.

There are a few researchers around the world who are paying attention to free-ranging dogs in their natural habitat. Anindita Bhadra, founder of the Dog Lab at the Indian Institute of Science Education and Research in Kolkata, has spent 16 years studying how dogs interact with humans, how they choose denning sites, and how they find food in India’s urban ecosystems. 

Bhadra is impressed with how well dogs have adapted to the stressors of city living. “They have moved from living on streets with bullock carts to now electric vehicles, and they have survived,” she says. “They are very adapted to occupy every niche that humans occupy.” 

Bhadra agrees dogs could be a useful model to study how other animals adapt to urban niches and how urbanization affects their behavior. But she also thinks they could help us make cities more inclusive for other species. Studying free-ranging dogs can help us understand what animals need to survive in a human environment—not just what they eat, but also what kinds of spaces they need for sensitive life events, like giving birth. That knowledge could help us design urban areas that provide urban wildlife safer spaces to rest, eat, and drink.

“How we provide for this coexistence is something the dogs can teach us,” Bhadra says. “Once we understand what their needs are, we can extrapolate that to other species.”

For her part, Hansen Wheat wants to study how natural selection is shaping free-ranging dogs’ distinct behavioral adaptations.

Urbanization is transforming the planet. As we continue to radically modify the environment, ever more species are being driven to extinction. Wynne says the key to understanding and slowing this loss is to study the occasional successes among the tragedies. And he says the enormous diversity of free-ranging dogs is one of those successes.

“We’ve sort of failed to notice that these animals we think of as almost human are actually the example par excellence of a species that has learned to succeed in human environments,” he says. “They can help us understand what leads to that success.”