okay so why did we domesticate the loud howling-barking canines and not the cute squeaky-trilling canines? (rhetorical)
A rhetorical question, but still quite an interesting one, given the human tendency to try to make pets out of basically any animal they come in contact with. For example, though the cats of today all descend from the African wildcat (Felis sylvestris lybica), there’s archaeological evidence that ancient people were ‘experimenting,’ shall we say, with taming a variety of other wild cat species. And people today certainly attempt to keep small canids such as fennec and red foxes as pets (as well as wolves or wolf hybrids, usually with disastrous consequences).
So what makes certain animals candidates for long-term domestication? We can go over the list of traits the ancestors of most domestic animals share- that is, low fear responses, ability to live in close quarters with many others, adaptability and non-specialization, rapid growth rate, and of course, a sociable adult lifestyle. (Wildcats and ferrets are rather interesting exceptions to this last qualifier, but they are also surprisingly behaviorally flexible.)
What I think often gets ignored in the discussion of domestication is the other half of the equation- the human half. Why haven’t we domesticated every animal with the above-mentioned traits? Because we don’t always need to. I suspect that the attempts to domesticate small carnivores mostly stopped once stable populations of cats were established, because the niche of small rodent-catcher was filled. Similarly, early domestic dogs were versatile enough to fill multiple roles, such as guardians, hunting companions, pack animals (as in, carrying things), and eventually herders, negating the need for any sustained attempts to domesticate other canids.
Of course, I don’t believe this to be the whole story, just something that’s often left out of the narrative. Other things to consider that might make wolves better candidates for domestication than either dholes or African wild dogs is their diet. Wolves are carnivores, but can adapt to not only a variety of different meat sources but also different plant food sources as part of their diet. Conversely, dholes and African wild dogs have much more rigid dietary needs. I can’t think of a single paper I’ve read that includes anything but meat in their diets, and of that meat, a relatively shallow pool of prey. This makes it less likely that they would follow the whole “eat human trash and become human treasure” path that the wolves that were ancestral to modern dogs did.
Wolves are likely more behaviorally adaptable, too, despite the fact that they live in smaller social groups than the other two species do. From what I have read in the few accounts of people who’ve attempted to domesticate wild dogs, such as naturalist Brian Houghton Hodgson, they rapidly grow shy and aggressive as adults even when hand-reared. (Another factor often mentioned in particular is their extraordinarily strong stench. They are stinkers.) Both these species may be more fearful than wolves, given that neither are apex predators in their native environments, with hyenas, leopards, and lions or tigers to contend with.
Wild dogs of both Asiatic and African varieties might also just be more dangerous to keep than wolves, despite the fact that they are both smaller in size. Both have specialized mobbing behavior and can kill their prey in seconds when in large groups. I’m reminded of a sad case of a small boy who fell into a wild dog enclosure in Pittsburgh and was killed almost immediately by the pack there.
So, in summation- and this is mostly my opinion here, not bolstered by much actual evidence- it was a mix of greater adaptability and sheer luck that led to wolves being the first domesticated animal, and only large domesticated canid.