How many species of wolves live in America? A new study suggests there is just one.
The new work, published Wednesday in Science Advances, finds that the gray wolf is the one true wolf in the United States. The red wolf, which lives in the Southern U.S., and the eastern wolf, now found primarily in central Ontario, are in fact coyote and gray wolf hybrids, the authors say.
"We found that the red wolves are about 75% coyote ancestry, and the eastern wolf has more gray wolf ancestry, about 75%," said Robert Wayne, an evolutionary biologist at UCLA and senior author on the study.
The distinction is not purely academic. Wayne said the findings could inform whether gray wolves continue to be protected by the U.S. Fish and Wildlife Service under the Endangered Species Act.
In August of 2000 a group of Canadian researchers published a paper arguing that the eastern wolf, long considered a subspecies of the gray wolf, was in fact its own species. Subsequent papers suggested that the eastern wolf's traditional range included the Great Lakes region and the 29 Eastern states.
This posed a problem for the gray wolves, who have been protected by the Endangered Species Act since the early 1970s.
When gray wolves were first protected, their historic geographic range was listed as including some of the same parts of the country that some scientists were saying had been occupied by the eastern wolf.
If in fact those areas had been the eastern wolf's range, the historical mistake could be enough to get the gray wolf bumped off the list of protected animals.
"It is written into the Endangered Species Act that if a taxonomic mistake is uncovered you can revoke the protection," Wayne said. "It's all dependent on taxonomy."
And so Wayne and his team set to work on determining once and for all the true origin of the eastern wolf, and the red wolf, while they were at it.
The group analyzed the genomes of 12 pure gray wolves from areas with no coyotes, three coyotes from areas where there were no gray wolves, as well as six eastern wolves and three red wolves. They were looking for any mysterious genetic material that was not gray wolf or coyote, and could be uniquely considered red wolf or eastern wolf.
"In humans from Eurasia you can pick up 1-4% Neanderthal DNA — in the red and eastern wolves we thought we might find 20-30% of genes that would be Neanderthal-like," Wayne said.
Instead, he said, the group found almost nothing that could not be explained as coming from coyotes or gray wolves.
"There is no evidence for distinct eastern or red wolf species," he said. "So the idea that the eastern wolf historically inhabited the Great Lakes area is wrong."
Wayne said it wasn't until the 1920s that coyotes even reached the Great Lakes area and began to interbreed with a dwindling gray wolf population — resulting in the hybrid animal known as the eastern wolf.
A similar process happened in the American South hundreds of years earlier, resulting in the red wolf.
Wayne hopes his team's findings will ensure that the gray wolf can continue to be protected under the Endangered Species Act. He said a decision on that from the U.S. Fish and Wildlife Service could come as early as this fall.
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