How human activities may be creating coywolves

red wolf

Red wolves like this one are more likely to mate with coyotes after a wolf’s mate has been killed, a new study finds.

Steve Hillebrand/USFWS/Flickr (CC-BY 2.0)

No one knows for sure exactly how far the range of the red wolf (Canis rufus) might have extended. By the time anyone started wondering, their numbers had severely dwindled, a result of antipredator control programs, habitat destruction and matings with coyotes (C. latrans). By 1980, the wolves were declared extinct in the wild. But the canids might have once been found across much of eastern North America into Canada, scientists believe.

Today, a small population of 80 to 100 red wolves prowls the Albemarle Peninsula in North Carolina, thanks to a U.S. Fish and Wildlife Service reintroduction program. Hunting the wolves is no longer permitted, but humans with guns may still be causing problems for the critically endangered species, a new study reveals. And it’s not just because of wolf deaths.

Justin Bohling and Lisette Waits of the University of Idaho in Moscow wanted to know what the factors were behind matings between red wolves and coyotes, which still occur. These interactions produce hybrids, sometimes known as coywolves, and are considered a major threat to the red wolf species. The threat is thought to be so big that USFWS removes any hybrids they come across. But little is known about why the matings occur.

The researchers took advantage of the fact that the USFWS continues to heavily monitor the red wolf population in North Carolina. Animals are tracked, and there is extensive genetic data for the wolves and their offspring. Bohling and Waits tallied up all the documented litters from 2001 to 2013. In that time, there were 126 litters that had two red wolves for parents and 30 that had a red wolf parent and a coyote parent.

Most of the hybridization events occurred between a male coyote and a female red wolf, usually a young one breeding for the first time. For 23 events, the researchers knew the history of the wolf. Of those, 18 pairings occurred after the female wolf lost her male wolf partner (red wolves usually form lifelong pair-bonds). Some of those losses were due to natural causes, but 11 occurred because a person had shot, poisoned or trapped the wolf. (The wolves look similar to coyotes — even scientists can’t always tell the difference from sight alone — so the killings may not have been intentional.)

The matings aren’t occurring simply because the red wolf and coyotes populations overlap. “The elimination of red wolf breeders during the breeding season forces reproductively active red wolves to quickly locate another mate,” the researchers write. And with few red wolves and lots of coyotes to choose from, inexperienced females may choose the wrong species of guy.

Future management of the wolves should therefore place more emphasis on reducing the numbers of wolves lost to gunshot, Bohling and Lisette conclude in the April Biological Conservation.

But local support for such efforts may be low. Earlier this year, North Carolina state regulators asked USFWS to end the reintroduction program and remove all the red wolves from the state. The state claims that the reintroduction program has failed and that the wolves have damaged private lands. A decision from USFWS on the future of the program is expected soon.

Sarah Zielinski

Sarah Zielinski is managing editor of Science News for Students. She has a B.A. in biology from Cornell University and an M.A. in journalism from New York University. She writes about ecology, plants and animals.

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