Home Forums Hunting & Shooting Hunter's Campfire DNA Study: Only One Kind of Wolf in North America

The first large study of North American wolf genomes has found that there is only one species on the continent: the gray wolf. Two other purported species, the Eastern wolf and the red wolf, are mixes of gray wolf and coyote DNA, the scientists behind the study concluded.

The finding, announced on Wednesday, highlights the shortcomings of laws intended to protect endangered species, as such laws lag far behind scientific research into the evolution of species.

The gray wolf and red wolf were listed as endangered in the lower 48 states under the Endangered Species Act in the 1970s and remain protected today, to the periodic consternation of ranchers and agricultural interests.

In 2013 the United States Fish and Wildlife Service recognized the Eastern wolf as a separate species, which led officials to recommend delisting the gray wolf. Conservationists won a lawsuit that forced the agency to abandon the plan.

The new finding sharpens a scientific question at the heart of that debate: How should the Endangered Species Act address threatened animals that are hybrids?

“What’s very exciting about this paper is that it’s using extremely powerful tools to address longstanding, challenging questions in conservation,” said Ryan Kovach, a research wildlife biologist at the United States Geological Survey who was not involved in the new study.

When Europeans arrived in North America, wolves roamed much of the continent. Farmers and ranchers almost entirely eradicated them from what is now the United States.

Over the past four decades, conservation efforts have helped a few wolf populations recover in the Rocky Mountains and around the Great Lakes. In 2015, the Fish and Wildlife Service estimated there were 5,505 wolves in the continental United States.

Those efforts were only possible thanks to the Endangered Species Act, established in 1973. The law led to a recovery program for a species known as the red wolf, or Canis rufus, believed to have originally lived in the Southeast. The last red wolves were removed from the wild in 1980, and captive-bred animals were released into the wild beginning in 1987.

The gray wolf, or Canis lupus, once ranged from the Rockies to New England. In 1978, the Fish and Wildlife Service declared it to be threatened in the lower 48 states.

In 2000, some scientists began to argue that the eastern population of gray wolves was in fact a separate species, which they called Canis lycaon. The Fish and Wildlife Service recognized that species in 2013, and officials argued that the gray wolf, now deemed to be limited to the western United States, was doing well enough to be taken off the list.

The new analysis, published in the journal Science Advances, paints a profoundly different portrait of the American wolf.

Bridgett M. vonHoldt of Princeton University and her colleagues sequenced the genomes of 12 gray wolves, six Eastern wolves, three red wolves and three coyotes, as well as the genomes of dogs and wolves from Asia.

Dr. vonHoldt and her colleagues found no evidence that red wolves or Eastern wolves belong to distinct lineages of their own. Instead, they seem to be populations of gray wolves, sharing many of the same genes.

Sign Up for the Science Times Newsletter
Every week, we'll bring you stories that capture the wonders of the human body, nature and the cosmos.


What really sets Eastern wolves and red wolves apart, the researchers found, is a large amount of coyote DNA in their genomes.

The new study revealed that coyotes and North American wolves share a remarkably recent common ancestor. Scientists had previously estimated their ancestor lived a million years ago, but the new study put the figure at just 50,000 years ago.

“I could not have put money on it being so recent,” said Dr. vonHoldt.

That ancestor gave rise to two species — the predecessor of today’s gray wolves and that of today’s coyotes — somewhere in Eurasia. Dr. vonHoldt said that the two species then migrated into North America.

There, coyotes evolved into small predators that specialize in taking down smaller prey. Wolves took a different path, relying on their larger size and great speed to prey on moose and other big mammals.

As wolves were killed off in the East, coyotes spread from the Midwestern prairies over the past two centuries to take their place. Surviving wolves interbred with the coyotes, producing hybrid offspring.

Dr. vonHoldt and her colleagues found that the genomes of Eastern wolves that lived in Algonquin Provincial Park in Ontario are half gray wolf and half coyote. Red wolves are even more mixed: Their genomes are 75 percent coyote and only 25 percent wolf.

Some wolf experts were startled by the finding and said it would require further support.

Linda Y. Rutledge, an expert on Eastern wolves, questioned whether the new study was sufficient to reject them as a separate species. Two Algonquin wolves that were part of the new study, she said, lived during a period when hybridization between coyotes and wolves was unusually common.

“They’re potentially not representative at all,” she said.

Despite her concerns, Dr. Rutledge joined Dr. vonHoldt’s lab as a research associate last year to participate in a new study on wolves, called the Canine Ancestry Project. The researchers are pooling their samples of DNA to study up to 100 wolves, coyotes and dogs from every state in the continental United States, as well as in Canadian provinces.

Robert K. Wayne, an evolutionary biologist at the University of California, Los Angeles, who helped conduct the new study, said the mixture of coyote and wolf DNA highlighted the need for a more sophisticated approach to conserving biological diversity.

Red and Eastern wolves still deserve protection despite their high level of coyote DNA, Dr. Wayne said, because they still carry the DNA of an endangered species: gray wolves.

With the proper management of the species’ habitat, he added, natural selection could help the wolf genes become more common again.

Yet the Endangered Species Act offers no guidance about what to do with hybrid animals.

“We put things in baskets, but it doesn’t work that way in nature,” said Dr. Wayne. “We need to have a hybrid policy.”

Even if they are not pure wolves, Dr. Rutledge said, hybrid animals still play a crucial role in eastern forests as top predators. “If it can kill deer in eastern landscapes, it’s worth saving,” she said.

Wolves are not the only animals challenging traditional taxonomy. Many related species are trading genes through hybridization, either naturally or because of human activity.

“It’s a fairly broad swath of diversity,” Dr. Kovach said. “And more concerning, it’s increasing.”

http://www.nytimes.com/2016/07/28/s...egion=bottom-well&WT.nav=bottom-well

Maybe this will be explained further in next week's episode of "Zoo"?

Mike

I seriously doubt it.

So on the chance that wolves might be carrying some coyote DNA, just shoot the coyote part. If the wolf part dies, too, it's just to keep the species pure....

Preserving presumed red wolves (or "eastern" wolves or Mexican wolves) because the wolf DNA that they carry may be unique seems to be stretching it to me. There is no reason to believe that the wolf DNA in the genome of red wolves, Mexican wolves and/or "eastern" wolves is not present in existing populations of gray wolves. If the gray wolf is allowed to repopulate its former range, these other subspecies or "distinct population segments" will quickly disappear and "wolf management" will be greatly simplified.

Well, if wolves have coyote DNA, then it stands to reason that coyotes have wolf DNA as well. So following conservationist logic, we had better throw them on the endangered species list too.

But seriously, with a common ancestor that close, can they even truly be considered a separate species? We could almost consider the coyote to be a sub-species/variant of wolves.

Umm -- there's only one species of grizzly, one species of moose, etc. But lots of sub-species of all of them. Wolves are wolves, but they range from those little Mexican guys to the big Mackenzie's that they stuck in Yellowstone.

There was always some disagreement on northern wolves (Canada and AK) being different than southern wolves (extinct in lower 48 and mexico). The red wolves being part wolf and part coyote has been know for some time but they were able to breed as species.

I didn't see the Mexican mentioned in the article. How would this study relate to it?

I'm not sold on this report! Eastern Oregon coyotes are killed by wolves, this is documented by ODFW! I guess some horny male wolf might have knocked of a piece of coyote, but I can't see it going the other way. Also if they are hybrid then none fit under endangered species act.

If there are wolves with coyote DNA -- and if dogs and coyotes and wolves can interbreed and produce viable, fertile offspring -- and guess what, they CAN -- then wolves are just glorified DOGS.
That's the honest appraisal here. If two "species" interbreed and the offspring can reproduce, it's the same effing species and all the rest is fluff.

Well, that is the definition of a species.

That would be my question too. Aren't they just different subspecies?

It means they have been feeding everyone a plate full of horse hockey for awhile now...

Then, by the same argument, wouldn't eastern coyotes deserve protection? Eastern coyotes are coyote/wolf hybrids, just like the so-called "red wolf." In fact, why wouldn't this mean that the red wolf is actually an eastern coyote? (I've always thought the red wolf is actually an eastern coyote.)

I doubt anyone has ever argued that there are more than one species of wolf in North America, but clearly there are several subspecies.

Steve.