The black allele that exists in wolves and coyotes originated in domestic dogs and entered those species because of hybridization.
Ever since Meet the Coywolf appeared on Nature on PBS and then made a long run on Netflix, the concept of hybridization within closely related Canis species has captured the public imagination.
But what is interesting about hybrids in Canidae is they have only been documented within these Canis species, which are domestic dogs/ dingoes/gray wolves, Ethiopian wolves, coyotes, Eurasian golden jackals, and African golden wolves, and between swift and kit foxes where their ranges overlap. Sterile hybrids have been produced by crossing red foxes (usually silver phase) with arctic foxes (usually blue phase) in fur farms.
And as it stands right now, these are the only hybrids that have been documented.
This rarity is quite unusual, because the cat family has lots of hybridization by comparison. Intergeneric hybrids have been produced by crossing cougars with leopards, which are called “pumapards,” and hybrids have even been produced crossing ocelots and bobcats. Domestic cats have been hybridized with servals and leopard cats. Pantherine hybrids are famous, including the very real liger and leopon.
But no one has produced a true intergeneric hybrid in Canidae. There are rumors of a dhole-Eurasian golden jackal hybrid from British India, but the account of this animal is literally one sentence in a book by Reginald Pocock. The Thai Bangkaew dog was said to be a dhole hybrid, but the current thinking is that the wild dog in its background is the Eurasian golden jackal. Rumors of a dog crossed with a crab-eating fox were passed around a few years ago, but I don’t remember anyone checking out this supposed hybrid.
No one has ever produced a real vulpine fox-dog hybrid. No one. I’ve run into several accounts of a creature called a “dox,” but they all existed before the discovery of DNA.
But no one has seen a dox since then.
It is really interesting that hybridization is far less common in Canidae than Felidae, and it certainly worth exploring why.
Losing chemical interfertility clearly does not happen at the same rate, and the mechanisms by which this happens are not clearly understood.
As I noted in an earlier post, I am skeptical that the extinct North American “cheetahs” are the root cause of the pronghorn’s speed. I am not alone in this skepticism, but my skepticism is rooted in the evasion strategy that pronghorns use. They flat-out run, whereas the antelope that are part of the true cheetah’s prey sources often use complex twisting and turning behavior to evade the swift cat. The pronghorn is a super long-distance runner, and its evasion strategy is more in keeping with a creature that was hunted by long-running dogs or perhaps the only hyena that ever existed on this continent.
I’ve been thinking a lot about cheetahs lately. A few weeks ago, I was watching an episode of Nature on PBS in which the filmmakers were putting cameras on various animals. They put some cameras on some young cheetahs, and I was somewhat surprised at a species they seemed to like to target. They were constantly harrying and harassing bat-eared foxes.
It was at that moment that two ideas I had in my head were connected. I’d been toying around with writing something on this space about the Afrikaans name for the bat-eared fox, which is “draaijakkals.” The name means “turning jackal,” and the animal got this name because when a dog would get after one, it would start twisting and turning as it ran. Now, this certainly would be the fox for sighthound enthusiasts to course.
But it really doesn’t need this skill to hunt its prey. In South Africa, it was believed they were a threat to lambs, but the truth is that 80-90 percent of their diet consists of one species of harvester termite, which don’t require much chasing.
Their running behavior is an evasion strategy, not a hunting strategy.
Why does this fox have such a gazelle-like evasion strategy? Well, I will engage in a bit of speculative zoology here:
Cheetahs are not migratory species, but many of their prey sources are. And during times in which ungulates can’t be hunted, some of them could very well come to rely upon bat-eared foxes as their favored prey.
Although bat-eared foxes do derive from a basal lineage of vulpine foxes, the exact species first appeared in the fossil record 800,000 years ago. And they evolvedin areas where cheetahs were present.
This little hypothesis has some problems. One of them is that cheetahs don’t often target bat-eared foxes, but we do know cheetahs will when they are unable to hunt ungulates.
But does cheetah predation on bat-eared foxes happen enough to have had that effect upon the canid’s evasion strategy?
I don’t know if we can answer that question, but it seems to me that the bat-eared foxes’ odd twisting and turning and doubling back behavior comes from cheetah predation as a selection pressure.
It is worth considering. Maybe I am way off, but I don’t know of any other canid that runs from predators in this fashion.
I love Kentucky Afield, but I have some problems with the terminology in this clip.
The hunter in this video calls the coyote an invasive species in part because it killed some cats.
Now, cats clearly are an actual invasive species. They exist at much higher densities than any native mesopredators, and the truth is that anything that keeps cats numbers down or keeps them scared out of their minds to leave the house is a good thing for many small birds, mammals, reptiles, and amphibians.
The genus Felis is not native to any place in the Americas. Had Europeans never come over here, we would have our native cat species, which would exist at numbers that were controlled through competition with other native predators and the fluctuating numbers of prey species.
If any animal that has been introduced since the time of colonization has caused ecological chaos, it is the domestic cat.
This is what ecologists say, but cats have good publicity. They have a fan club. I can’t say that I’m in it, but I can see why some people like them. They are like a mentally deficient dog that doesn’t require walks or much training, but they are far more intelligent than guinea pigs and better company than Syrian hamsters.
The same cannot be said for the coyote. Those of us who live outside the proposed original range for coyotes tend to think of them as a Western species that came into the East, but the truth is we have fossil evidence of Pleistocene coyotes in the East, including in West Virginia.
We also have accounts of anomalous wolves. For example, John Smith described the “wolues” around Jamestown as not being much larger than English foxes. It is usually suggested that these Jamestown wolves were red wolves. Ignoring the real problems about what red wolves actually are, coyotes fit the description far better than anything we’ve ever called a red wolf.
It is very possible that coyotes existed in the East but in far smaller numbers than they do now. The wolf hunters and fur trappers who came into the continent took as many wolves as they could, and they didn’t take great lengths to catalog what they were killing. They just killed them, and they either got their bounty or sold the hides. And many Native American dogs went with them.
So I think it is possible that there were some coyotes in East, but their big range expansion didn’t happen until the extirpation of larger wolves.
Further, the entire genus Canis has its origins in this continent. The earliest forms of the genus was Canis evolved in North America 6 million years ago, though they were restricted to the Southwest and Northern Mexico, but coyotes and coyote-like canids were found throughout what became the United States during the Pleistocene.
The genus Felis didn’t appear here until permanent European colonization and settlement.
So this idea that you’re killing the coyote as the “invasive species” to protect the cat is a total perversion of the ecological concept.
It is also interesting that no one ever calls a red fox an invasive species in the United States– with the except of Eastern red foxes that have been introduced to California. The red fox was not found south of the Northern Great Lakes, Northern New York, and Northern New England, but it is now found over most of the Eastern states.
The red fox took advantage of the clearing of forests, which disadvantaged the gray fox, its main competitor, and came south in large numbers. They introduced themselves to the new territory in the same way that coyotes would later do as the wolves were killed off.
No one seriously considers the red fox to be an invasive species. It also has a record of being in parts of Virginia and Tennessee during the Pleistocene, but it did not exist when Europeans came.
Most states treat it as a proper game animal. Mine has a proscribed hunting and trapping season for them, but coyotes can be killed all year round.
But the “native” status of the two animals is fairly similar, and if these older accounts of anomalous small wolves in Pennsylvania and Virginia describe coyotes, then the coyote has a much stronger native status than the red fox.
“Invasive species” is a term that really does have a meaning to it, but it cannot be allowed to be used in such a way that it means any animal that inconveniences us.
We should use that term to mean animals that were introduced either by accident or intention and that have caused real ecological damage. I am thinking feral hogs here. And cane toads. And marmorated stink bug.
Natural History 