I’ve gotten a number of calls, comments, and texts from people who believed they had found a coyfox, a hybrid between a coyote and a red fox. It’s an understandable mistake to make. Many people, especially here in the Southeastern U.S., might encounter an animal that looks too big to be a fox but has reddish fur and a big, bushy tail.
As cool as it would be if they were… these animals aren’t coyfoxes.
In general, animals can crossbreed only if they’re very closely related and have the same number of chromosomes, or just a very slight difference in their number of chromosomes. For example, a horse has 64 chromosomes and a donkey has 62 chromosomes, and they are members of the same genus, Equus. Because of this, they can have offspring (mules), which happen to have 63 chromosomes, and are generally sterile.
Domestic dogs, coyotes, red wolves, and every subspecies of grey wolf are all very closely related. All these animals, which can be found in North America, are members of the same genus (Canis) and all have 78 chromosomes. They can cross freely and have fertile offspring.
A red fox is a member of an entirely separate genus from these animals, since they parted ways long ago in their evolutionary history. A red fox has 36 chromosomes (though interestingly, some of them can have one or two fewer or more). That’s a huge, huge difference between the number of chromosomes in a fox and in a coyote, so it’s essentially impossible for a living embryo to be born to both species… not to mention, a coyote would be very unlikely to choose to mate with a red fox in the first place.
Domestic dogs– even foxy-looking ones like shiba inus and Pomeranians– aren’t able to breed with red foxes, either. The only exception was in a laboratory study of the genetic differences between red foxes and dogs, where scientists were able to splice the genes of the two animals into one cell. Of course, that didn’t result in a dog-fox hybrid actually being born.
Red foxes don’t produce hybrids with other foxes, either. Although they could theoretically crossbreed with kit foxes or swift foxes, it’s never actually been known to happen. Grey foxes are only very distantly related to red foxes and can’t possibly reproduce with red foxes, either.
There was some speculation in recent years that red foxes might cross-breed with arctic foxes as a response to climate change, but that hypothesis was ruled out. It would have been pretty shocking since arctic foxes have 50 chromosomes— but the genetic tests revealed that the “hybrids” were just arctic foxes with unusually red summer coats.
So what’s the answer to the mystery of the coyfox? It’s both simpler, and more interesting, than you might expect! An animal that looks like a coyfox is, most likely, a coyote with either erythrism (a condition causing reddish fur coloration) or leucism (a condition causing blonde or gold coloration). Most coyotes with these genes are not “pure” coyotes, but distant descendants of wolves and feral dogs. Leucism, in some coyotes, has been linked to a male golden retriever who joined a coyote family decades ago in Newfoundland, while erythrism in Southeastern coyotes seems to be a legacy of the red wolf, which is now extinct in the wild.