The gray wolf is the only true wolf species in the United States. (AP Photo/U.S. Fish and Wildlife Service, Gary Kramer)

According to research published Thursday in Science Advances, red wolves and eastern wolves aren't truly wolves at all – they're coyote-wolf hybrids. That confirms something scientists had long debated: Canis lupus, the gray wolf, is actually the only wolf species in the United States. Neither the red nor the eastern wolf has any DNA that can't be tied to gray wolf or coyote origins. All three "species" are actually just gray wolf descendants with varying levels of coyote DNA.

The red wolf is actually mostly coyote, according to the study, with just around a quarter of its genes coming from the gray wolf. The eastern wolf is 25 to 50 percent coyote, and even gray wolves carry some small traces of coyote interbreeding in their DNA (in much the same way that many humans carry small percentages of Neanderthal DNA today).


Two captive red wolves. (AP Photo/The Virginian-Pilot,Hyunsoo Leo Kim)

The study also found that gray wolves and coyotes are much more closely related than previously assumed. While previous research had suggested that the two species had diverged around 1 million years ago, the new genetic analysis hints at a common ancestor 50,000 years ago.

Based on the traces of coyote DNA found even in "pure" wolves, the researchers suspect that these two closely-related species have frequently intermingled throughout the past few centuries. Gray wolves have become scarce in the United States – many populations have disappeared entirely – which made the remaining wolves more and more likely to pair up with coyotes as time went on. And as these hybrid creatures interbred with one another instead of with pure wolves, their coyote-like genes and characteristics became more prominent, giving them the appearance of an entirely new species.

The findings could have disastrous implications for the canines. The red wolf is currently protected by the Endangered Species Act (ESA), but the ESA doesn't protect hybrids.

“People think that species should be genetically pure, that there should be tidy categories for ‘wolf’ and ‘coyote.’ That’s not what we found,” lead author Bridgett vonHoldt, an evolutionary biologist at Princeton University, told Science Magazine. Instead of leaving the red wolf to its own devices, she and her colleagues say, conservationists should rethink their treatment of hybrids. They believe the eastern wolf should be protected as well, coyote genes be darned.

"Our findings demonstrate how a strict designation of a species under the ESA that does not consider genetic admixture can threaten the protection of endangered species," vonHoldt said in a statement. "We argue for a more balanced approach that focuses on the ecological context of genetic admixture and allows for evolutionary processes to potentially restore historical patterns of genetic variation."

On the other hand, the study could actually help gray wolves maintain their ESA protection: Because the United States Fish and Wildlife Service (FWS) listed eastern wolves as having a range that overlapped with gray wolves, the latter's protection was at risk of being thrown away on a technicality. For now, the FWS has reportedly declined to comment on the new findings – so there's no way of knowing which way the wind will blow for gray wolves and their hybrid cousins.

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