Natural History

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.