A side-striped jackal (Canis adustus), the jackal no one talks about.
We’ve always called the smaller wild dogs in the genus Canis jackals.
Historically, there were four species of jackal: the golden (Canis aureus), the black-backed (Canis mesomelas), the side-striped (Canis adustus), and the Simien (Canis simensis).
Some authorities considered they coyote (Canis latrans) to be a jackal, usually called “the American jackal.”
At one time, they were all placed in the genus Thous.
This, of course, assumed that these animals were all closely related to each other.
However, as we’ve looked at DNA analysis, the relationship between jackals shows that the term “jackal” is actually quite meaningless.
In 1994, an mtDNA study revealed that the Simien jackal had certain mtDNA sequences that were more similar to wolves than other jackals. It was thought to be a relict population of primitive wolves that came into Africa during the Pleistocene.
And from that time forth, the English name of this species was change to “Ethiopian wolf.” I don’t call it anything else.
However, as more work was performed on jackals, certain facts became evident.
Initial studies of black-backed, side-striped, and golden jackal mtDNA revealed that black-backs in East Africa had huge variances in their mtDNA. Golden jackals had mtDNA that was most similar to coyotes and wolves, while black backs and side-stripes were more similar to each other.
And then the phylogeny of the dog family was drawn from a high-quality sequencing of the dog genome revealed that golden jackals were much more closely related to coyotes and the wolf and domestic dog species than the Ethiopian wolf was. We still call them Ethiopian wolves, even though golden jackals are more closely related to actual wolves than those animals are.
The other issue revealed through this research was that Canis, as it is traditionally classified, is a paraphyletic genus. Modern taxonomy is generally concerned with classifying animals according clades. Clades are, by definition monophyletic. That is, they contain all the animals that descend from a particular lineage.
The dog genome research revealed that two species that are never traditionally classified as being part of Canis, the African wild (Lycaon pictus) and the dhole (Cuon alpinus), actually should be included there. It turns out that black-backed and side-striped jackals are more distantly related to the rest of Canis than these two species are.
And if we classify Canis with all the jackals, the Ethiopian wolf, and the wolf and dog species and leave out the dhole and African wild dog, we’ve created a paraphyletic genus that is not useful to modern taxonomy.
Some have suggested giving the two endemic African jackals their own genus.
And this would make Canis monophyletic without including the African wild dog and dhole.
However, the genus that would remain would include several species that are all chemically interfertile with each other (at least in theory). Species complexes exist throughout that part of the Canis, and delineating species is very difficult the species in this lineage.
Although Robert Wayne at UCLA has suggested that black-backed and side-striped jackals might be able to interbreed, no one has confirmed a hybrid between these two species. African wild dogs might be able to hybridize with dholes, but because they live on different continents and because they are both fairly endangered, no one has attempted to cross them. (There are persistent rumors that dholes can cross with domestic dogs. One dog breed, the Bangkaew dog from Thailand, is said to have derived from a dog/dhole cross. However, I don’t believe this claim has ever been tested through DNA analysis.)
All this research has revealed that how we have traditionally thought about the dog family is probably wrong.
The golden jackal is actually a primitive offshoot of the wolf lineage, just as the coyote in the New World is. The Ethiopian wolf is an even more primitive offshoot.
The two endemic African jackals are the two oldest living species in the Canis lineage. They are even more distinct from this lineage than dholes and African wild dogs are.
We do not have a good replacement word for jackal.
I’ve suggested that we call golden jackals “Old World coyotes” almost as a joke.
But I don’t have a good name for either of the two remaining jackal.
Because black-backed jackals are so scrappy, I’ve even suggested that we call them “wild Jack Russells.”
Whatever we call them, the term jackal, if it’s used to reflect close relationships between species, is utterly meaningless.
With the exception of the two found only Africa, it doesn’t refer to any animals that have a close relationship with each other.
It’s just a term we use for smaller wild dogs that are in some way related to wolves.
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