I’ve been looking into the black-backed jackal this week. At first I was checking into the possibility that they can hybridize with domestic dogs.
I am still skeptical that they can.
However, what I have found about this species is they are quite strange.
There are two populations of this species that are not contiguous. One exists in southern Africa, and the other exists in East Africa. The East African subspecies is larger than the southern African or “Cape” subspecies. It also does not howl and has a more carnivorous diet than the other subspecies. (The only howling jackal in East Africa is the golden jackal).
I have heard people claim that both of these are good enough reasons to consider domestic dogs a separate species from the wolf, but because we’re dealing with two subspecies of a jackal, an animal without all the cultural baggage the dogs and wolves have, it is universally accepted that these both represent Canis mesomelas.
Now, that was weird enough.
It turns out that the East African subspecies has rather amazing variance in its mtDNA sequences. Contiguous populations have been found to have as much as 8 % variance in that part of their genome. That’s a lot, and the questions it has raised have not been answered. We do not know why there is so much variance within this single subspecies.
If I were a molecular geneticist, this is the dog species that would have my attention. After all, the dog genome has been decoded, and we are starting to find answers about the evolutionary relationship between dogs and wolves.
No one has answered these questions, and because it is now accepted that the black-backed jackal and the side-striped jackal are the oldest members of Canis, these animals might have a lot to tell us about the other species in this genus.
Black-backed jackals are much more aggressive with other jackals and with each other than either golden or side-striped jackals, and although they are capable of killing larger prey than themselves because they just that bold.
In essence, a black-backed jackal is a naturally occurring Jack Russell terrier.
They are also probably the first species of the genus Canis with which hominids and later modern humans would have had some familiarity. These are probably the first “dogs” to scavenge off of hunter-gatherer kills.
Yet no studies have found that these animals have contributed to the dog genome. There are plenty of dogs in East and Southern Africa that look like black backed jackals, and some traditional societies call such dogs “jackal-dogs.” I have not heard of any verified hybrids between these two species, although they are often speculated.
I don’t think I can believe until I see a study that shows a definite hybrid, because I think what we’re seeing here is that jackals and dogs are developing similar conformation in what is called parallel evolution. Both of these animals live in the same habitat and both share a common ancestor. However, the ancestor for the dogs was the Eurasian wolf, which evolved from different line of the ancient Canis species. When the two species have to live in the same habitat and eat the same food, the Eurasian wolf derived species begins to develop adaptations and phenotypes that are similar to the native East and Southern African species. (This differs from convergent evolution because convergent evolution is when two entirely unrelated species develop similar features and adaptations– like the wolf-like canids and the Thylacine.)
Now, that’s the established view. This is also pretty much what I think is happening here.
However, I was confronted with a study that did make me scratch my head.
In South Africa’s Western Cape Province, bones dating to the later Stone Age that were assumed to be domestic dogs , simply because of their proximity to human settlements. When the DNA was tested, these “dogs” all turned out to be black-backed jackals. That means that humans have had a relationship with Canis mesomelas that could have become like the relationship between humans and the wolves that became dogs.
It is also possible that there were populations of black-backed jackals that were semi-domesticated before the arrival of wolf-derived domestic dogs. When these dogs arrived, they replaced the semi-domesticated black-backed jackals as the most common canids in the camps.
That we have never been able to fully domesticate these jackals is another big question to the Coppinger hypothesis, because it is very likely that these jackals have been relying upon human kills and the excesses of civilization for a very long time. Yet there is no evidence of fully domesticated form of black-backed jackal, which would definitely be genetically distinct from the wolf-derived domestic dogs.
Now, I found all of this out through a discussion on the blog and through e-mail with a reader who has seen golden jackals and dogs live in close proximity in India. This reader is skeptical of the evidence that dogs are derived from C. lupus and thinks that jackals did play some role. I am willing to admit that the golden jackal and Ethiopian wolf may have played some minuscule role, as could the coyote. However, black-backed and side-striped jackals probably did not.
I am open to the possibility that such hybrids exist, but I want proof n terms DNA evidence. I know these “Africanis” dogs look like jackals, but as we have seen time and again, looks alone cannot indicate that sort of relationship.
I want to thank Gurjinder Sahota for alerting me to these studies, and at least opening my mind about the possibility that black-backed jackals could hybridize with domestic dog and that jackals might be an ancestor of the domestic dog. Most of the links in this post actually come from our discussions on this blog and via e-mail.
Although I was aware that East African black-backed jackals had wide variance in their mtDNA sequences, I had no idea that ancient African dog remains have been found to be black-backed jackals.
I think the really big question is why black-backed jackals were never turned into true domestic animals. I think the big reason may have to do with their heightened aggression towards their social partners. I don’t think hunter-gatherers would tolerate that sort of aggression in a pet , which is one reason why I think the original wolf populations were far less aggressive towards their social partners than modern wolves are now. Further, both wolves and men had similar ecological niches, which is the basis of Schleidt and Shalter’s theory about the co-evolution of man and dog.
To me, this questions all lead back to one major conundrum:
Why wolves and not these others?
I still think there is a chance that a semi domesticated “dog” derived from black-backed jackals may have existed in southern Africa.