How did a canine hybrid, ‘coywolf,’ emerge in front of our eyes?

A hybrid of coyote, wolf and dog that has developed over the last century or so, has many advantages over the purebred versions.

It seems that a hybrid of coyote, wolf, and dog DNA makes for a potent mix, as scientists have observed in a fit, new canid family member that’s been spreading through the eastern part of North America.

The “coywolf” – also known as the coydog, the eastern coyote, the tweed wolf, the brush wolf, the northeastern coyote, or the new wolf – was first described by scientists in the 1960s. Its population has quickly grown to millions and is quickly expanding into the southeast, drawing on the most advantageous features of each of the canid members that make up its hybridized DNA to spread and flourish in areas that have traditionally been inhospitable to purebred coyotes and purebred wolves.

“We’ve known for a while that most Eastern coyotes are hybrids to some degree, and now we’re finding a greater degree of hybridization than anyone expected,” Javier Monzón, an evolutionary biologist at Pepperdine University, told The Washington Post last year.

Dr. Monzón studied the genetic makeup of 427 of the animals in ten northeastern states and Ontario, concluding in a 2013 paper that coywolves are about 62 percent coyote, 27 percent wolf and 11 percent dog.

This mix brings big advantages, reports The Economist, as coywolves are twice as big as coyotes, with larger jaws, more muscle and faster legs. One coywolf could take down a small deer, while a pack of them can likely kill a moose.

Banking on its wolf-inspired love for hunting, coywolves can catch prey in both open terrain and densely wooded areas, “And even their cries blend those of their ancestors,” reports the Economist. “The first part of a howl resembles a wolf’s (with a deep pitch), but this then turns into a higher-pitched, coyote-like yipping.”

The DNA coywolf has inherited from man’s best friend may have counteracted its wolf instinct to avoid humans, some scientists believe, allowing it to spread and thrive among the people and noise of urban areas, where it can now commonly be found.

Roland Kays, director of the biodiversity lab at the North Carolina Museum of Natural Sciences told the Economist that this is an “amazing contemporary evolution story that’s happening right underneath our nose.”

Biologists suspect that the interbreeding that led to the coywolf began a century or two ago, when wolf populations in southern Ontario began declining as humans began clearing their forest habitat for farming, and to being killed in retaliation or anticipation of their deadly interactions with the humans who took over their land.

Deforestation simultaneously allowed coyotes that had previously lived in the plains between the Rocky Mountains and the Mississippi River to migrate northeast where they encountered attractive breeding partners in what was left of the wolves and in farmers’ dogs.

And thus the coywolf was born.

This type of hybridization among mammals has rarely been documented, reported Jonathan G. Way, a research scientist at Clark University, in a 2013 paper in The Canadian Field-Naturalist journal. Though it’s common among amphibians, insects, birds, plants and fish.

Dr. Way says that the coywolf has evolved into a new species, arguing that its morphological and genetic branching off from its ancestors qualifies it for its own label.

But the verdict is still out among scientists. As the the Economist reports, one species is commonly defined as a population that doesn’t interbreed with outsiders. Since coywolves continue to mate with dogs and wolves – mammals that are all in the Canis genus – they may be a subspecies, not a separate species.