In New England today, trees cover more land than they have at any time since the colonial era. Roughly 80 percent of the region is now forested, compared with just 30 percent in the late 19th century. Moose and turkey again roam the backwoods. Beavers, long ago driven from the area by trappers seeking pelts, once more dam streams. White-tailed deer are so numerous that they are often considered pests. And an unlikely predator has crept back into the woods, too: what some have called the coywolf. It is both old and new — roughly one-quarter wolf and two-thirds coyote, with the rest being dog.

The animal comes from an area above the Great Lakes, where wolves and coyotes live — and sometimes breed — together. At one end of this canid continuum, there are wolves with coyote genes in their makeup; at the other, there are coyotes with wolf genes. Another source of genetic ingredients comes from farther north, where the gray wolf, a migrant species originally from Eurasia, resides. “We call it canis soup,” says Bradley White, a scientist at Trent University in Peterborough, Ontario, referring to the wolf-coyote hybrid population.

The creation story White and his colleagues have pieced together begins during European colonization, when the Eastern wolf was hunted and poisoned out of existence in its native Northeast. A remnant population — “loyalists” is how White refers to them — migrated to Canada. At the same time, coyotes, native to the Great Plains, began pushing eastward and mated with the refugee wolves. Their descendants in turn bred with coyotes and dogs. The result has been a creature with enough strength to hunt the abundant woodland deer, which it followed into the recovering Eastern forests. Coywolves, or Eastern coyotes, as White prefers to call them, have since pushed south to Virginia and east to Newfoundland. The Eastern coyote is a study in the balancing act required to survive as a medium-size predator in a landscape full of people. It can be as much as 40 percent larger than the Western coyote, with powerful wolflike jaws; it has also inherited the wolf’s more social nature, which allows for pack hunting. (In 2009, a pack of Eastern coyotes attacked and killed a 19-year-old Canadian folk singer named Taylor Mitchell in Cape Breton, Nova Scotia.) But it shares with coyotes, some 2,000 of which live within Chicago’s city limits, a remarkable ability to thrive in humanized landscapes.

“We’re kind of privileged in the last 100 years to watch the birth of this entity,” White told me, “and now the evolution of this entity across this North American landscape that we’ve modified.” Evolutionarily speaking, coyotes diverged from gray wolves one million to two million years ago, and dogs from wolves roughly 15,000 years ago. Yet over the past century, as agriculture moved to the Midwest and California, farmland in the East reverted to woodlands. The rise of fossil fuels reduced the demand for firewood. Forests spread, and deer and other prey proliferated, while human intolerance for wolves kept a potential competitor at bay.