A new study claims that there is only one distinct species of wolf indigenous to North America, the gray wolf.

The study, published Wednesday in the Science Advances journal, debunks the theory that the red wolf found in southern U.S. and the eastern wolf found in central Ontario are also distinct species living in North America. Scientists say the red wolf and the eastern wolf are just gray wolves with coyote DNA.

“The recently defined eastern wolf is just a gray wolf and coyote mix, with about 75 percent of its genome assigned to the gray wolf,” senior author and professor at the University of California, Los Angeles, Robert Wayne reportedly said.

Researchers believe that the gray wolf and the coyote mixed a couple of hundreds of years ago in southern U.S., which the scientists say would result in physically unique wolves but not a unique species.

According to reports, the U.S. Fish and Wildlife Service had suggested that the gray wolf be removed from its list of endangered species due to a factual error. The organization had incorrectly stated that the wolf lived in the Great Lakes region and in 29 eastern states when in reality that area was occupied by the eastern wolf and never by the gray wolf. 

“We found no evidence for an eastern wolf that has a separate evolutionary legacy. The gray wolf should keep its endangered species status and be preserved because the reason for removing it is incorrect. The gray wolf did live in the Great Lakes area and in the 29 eastern states,” Wayne said.

But reports said that this could mean the red wolf and the eastern wolf might lose protection since U.S. law does not protect hybrids.