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Wild Things

The weird and wonderful in the natural world

Sarah Zielinski

Wild Things

Wild Things

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.

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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.


Cliff swallow breeding thwarted by bird version of bedbugs

By Sarah Zielinski 12:15pm, February 18, 2015
A 30-year study of cliff swallows in Nebraska finds that the birds will abandon nests, rather than have a second brood, when their homes are infested with swallow bugs.

Fertile hermit crabs turn shy

By Sarah Zielinski 11:00am, February 13, 2015
Male hermit crabs that aren’t carrying much sperm are bolder than their more fertile brethren, a new study finds.
Animals,, Ecology,, Conservation

Cats and foxes are driving Australia’s mammals extinct

By Sarah Zielinski 11:56am, February 11, 2015
Since the arrival of Europeans in Australia, a startling number of mammal species have disappeared. A new study puts much of the blame on introduced cats and foxes.
Animals,, Biophysics,, Evolution

Toads prefer to bound, not hop

By Sarah Zielinski 2:30pm, February 6, 2015
The multiple hops made by toads are really a bounding motion similar to movements made by small mammals.

Huge, hollow baobab trees are actually multiple fused stems

By Sarah Zielinski 11:54am, February 4, 2015
The trunk of an African baobab tree can grow to be many meters in diameter but hollow inside. The shape, researchers say, occurs when several stems fuse together.
Climate,, Animals,, Oceans

Warming Arctic will let Atlantic and Pacific fish mix

By Sarah Zielinski 12:00pm, February 2, 2015
The ultra-cold, ice-covered Arctic Ocean has kept fish species from the Atlantic and Pacific separate for more than a million years — but global warming is changing that.

Ant-eating bears help plants

By Sarah Zielinski 5:44pm, January 27, 2015
A complex web of interactions gives a boost to rabbitbrush plants when black bears consume ants.

If pursued by a goshawk, make a sharp turn

By Sarah Zielinski 7:00am, January 22, 2015
Scientists put a tiny camera on a northern goshawk and watched it hunt. The bird used several strategies to catch prey, failing only when its targets made a sharp turn.
Animals,, Evolution

Cringe away, guys — this spider bites off his own genitals

By Sarah Zielinski 7:00am, January 20, 2015
After sex, a male coin spider will chew off his own genitals, an act that might help secure his paternity.

Lemurs aren’t pets

By Sarah Zielinski 4:05pm, January 16, 2015
The first survey of lemur ownership in Madagascar finds that thousands of the rare primates are held in households.
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