The Mystery of the Coywolf

Is it a coyote? A wolf? Or something else entirely?
The Mystery of the Coywolf

They are bigger than their Western kin. Their heads are blockier, their legs are longer and their snouts a little shorter. In many ways, Eastern coyotes resemble a wolf. But, says at least one biologist, don’t call them coywolves. Dr. Roland Kays, a research associate professor at North Carolina, says a true “coywolf” is “not a thing.”

“In order for it to be a true coywolf, it would have to be the result of a pure coyote breeding with a pure wolf,” says Kays. “That happened, but it was likely a very long time ago. What we are seeing now is not a unique species.”

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Despite Kays’ objection to the term, it’s become ingrained in the media and among many hunters in the Eastern United States. Television network PBS devoted an hour-long episode of Nature to the phenomenon. It was called “Meet The Coywolf.” Countless articles have included the term in their headline or somewhere in the body of the text. Photos of Eastern hunters hoisting coyotes on various Facebook pages come with a slew of comments proclaiming the animal a “coywolf.”

Genetic testing has found that coyotes in the Northeast and Mid-Atlantic regions do indeed have wolf genetics in them. In some animals, wolf genes account for as much as 25 percent of their genetic makeup or as little as 8 percent. However, the mere presence of wolf genetics does not mean the animal is a true hybrid.

It does, however, mean Eastern coyotes show a number of wolf-like characteristics. They are indeed larger. Kays has verified an adult male Eastern coyote weighing 52 pounds. Male Western coyotes rarely exceed 40 pounds. One study determined that female Eastern coyotes were 21 percent heavier than male Western coyotes. That size difference is a direct result of crossbreeding with Eastern gray wolves. So are other physical characteristics.

Eastern coyotes also have domestic dog genetics, which would explain coloration or color patterns that resemble domestic dogs. In some instances, domestic dogs make up as much as 11 percent of an Eastern coyote’s genetics, although other coyotes only have 8 percent.

How much wolf or dog is in each Eastern coyote depends on a number of factors. Mostly, the region in which the animals live plays the largest role in the amount of wolf genetics in an individual animal. Specifically, coyotes in the Northeast tend to have the highest percentage of wolf genetics for the simple fact that they are closest to the origins of those genes. As they moved south, they were more likely to breed with other coyotes, diluting the wolf genetics.

Researchers determined that coyotes and wolves crossbred starting about 100 years ago as coyotes migrated East. That’s likely when wolf numbers were at their lowest point in the Great Lakes region due to widespread persecution. Wolves were killed indiscriminately by hunters, farmers and others. Coyotes were starting to fill the void, spreading East along a northerly route through Canada above the Great Lakes and through a route south of the Great Lakes.

Although wolves were extirpated from the Eastern United States as early as the early 1800s, coyotes took a century to make it to the Northeast. Kays says that has to do with the habitat more than anything.

“Coyotes are open-country creatures. The habitat along their northern migration route is heavily forested, so it took them a long time to make their way through that forest,” explains Kays.

As they spread eastward, those coyotes traveling through Canada bumped into the occasional wolf where, says Kays,
the larger male of the two typically mated with the smaller female. Most likely, that meant male wolves mated with female coyotes.

Migrating coyotes also bumped into stray or free-roaming dogs and bred with them starting around 50 years ago. Why so late?

“The first coyotes to arrive in some parts of the East were more likely to encounter stray dogs than other coyotes,” says Kays.

As lone female coyotes encountered male dogs, the larger male dogs simply did what came naturally. As more coyotes moved East, however, those new coyotes and the current ones interacted with dogs less and less. Dog genetics became less prominent.

“Animals tend to avoid breeding across species, particularly when there are enough of their own species to breed with,” says Kays. “That’s why Western coyotes typically do not have wolf or dog genetics in them.”

It’s also why various color phases that show up in the East are virtually non-existent in the West. Coyotes simply don’t need to breed with dogs so they don’t.

“Male coyotes typically help raise the pups. Male dogs don’t, so it’s unlikely a dog/coyote hybrid pup would even survive, even if they did breed,” says Kays.

NCC Conservation Officer Richard Moore holds a coywolf at La Pêche Lake in Gatineau Park in Quebec. (Credit: National Capital Commission)

It’s not impossible for Western wolves to breed with Western coyotes, either. Although gray wolves were reintroduced to the Yellowstone region in the 1990s, their numbers remain low enough that a wandering male might mate with a willing female coyote. However, it’s unlikely, in part because of the size difference, but also because a wolf would rather kill a coyote than breed it.

Gray wolves in Eastern Canada are somewhat smaller than their Western kin, which is the most plausible explanation for crossbreeding between wolves and coyotes as the two crossed paths.

Coyotes in the Southeast likely arrived via two primary routes. The first, and likely the one that accounted for the most coyotes, was a natural migration that occurred across the Gulf states and Tennessee, using bridges as a means of crossing the Mississippi River. Some may have actually swam across. As Kays says, coyotes prefer more open habitat typical of the Western United States, which is likely why it took so long for coyotes to show up in the East in great numbers. Natural obstacles, most notably the Mississippi River, also delayed the migration.

The other method was a direct result of stocking efforts by hunters who brought coyotes east as another hunting opportunity.

Research has found that the two natural migration routes met somewhere in Virginia. Since coyotes in the South-central states west of the Mississippi — Texas, Arkansas and Louisiana — had no interaction with wolves as they migrated east, they have only a very small amount gray wolf genetics.

However they got here and whatever they are, coyotes are established in the Eastern United States and they have no trouble finding a mate of their own species now. As Kays says, a coyote would rather kill a dog than mate with it.

So what will become of the wolf and dog genetics? Kays thinks the genetic traits that help them survive — stronger jaws, blockier heads and shorter snouts, for example — will likely continue to remain through a process of positive selection. Those characteristics help Eastern coyotes kill and eat deer, although their primary prey remains small mammals. Traits that have little influence on long-term survival will eventually fade out. This genetic “drift” is a process of natural selection and will ultimately settle into an equilibrium over time.

What it turns into remains to be seen, and Kays wonders if Eastern coyotes could be designated as a subspecies of Western coyotes, just as there are numerous subspecies of whitetail deer. Some researchers are suggesting as much, but such a debate will likely take years, even decades for scientists to hash out.

Most likely though, Eastern coyotes will be nothing more than a coyote, just as the Virginia whitetail subspecies (Odocoileus virginianus virginianus) is the same species as a Texas subspecies (Odocoileus virginianus texanus).

“Whitetail deer evolved to adapt to their environment. Eastern coyotes are doing the same thing,” says Kays.

Another example of this evolutionary adaption is gray wolves. They inhabit such diverse regions of the world as Alaska, Mexico, Israel, Spain, Iran, Russia and China. While they may have subtle differences in their physical characteristics and their life habits, they are the same species. The Eastern coyote is undergoing the same physiological changes to adapt to the environment. Coyotes in the desert Southwest tend to be smaller, for example, while those in Canada are larger. Kays refers to this phenomenon as “ecotypes.”

“It’s most certainly a rapid evolution that is taking place right before our eyes,” he adds. “We are in the very early stages of research of Eastern coyotes, so we have a lot to learn.”

Featured image: Photograph of a coywolf taken in February 2014 in Gatineau Park, Quebec, Canada. (Credit: National Capital Commission)


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