It began with jackals

Canis cedazoensis

Canis cedazoensis was an early species of the wolf-coyote-jackal tribe. It lived what is now the American Southwest and Northern Mexico until 300,000 years ago. It probably scavenged kills of bigger predators and lifted off the fawns of the various species of pronghorn.

Conventionally, we believed that the lineage from which this jackal-like canid gave rise to the wolf, the coyote, and the golden jackal. We based these assessments on comparative morphology from fossil and subfossil remains, and it all made sense.

These jackal-like forms entered Eurasia and Africa. They gave rise to the Xenocyon, the first wolf-like canid to evolve of this lineage.  The Xenocyon gave rise to the dhole and the African wild dog. Then the actual wolves evolved in Eurasia, and they walked back into North America to found the Armbruster’s wolf and the Dire wolf. They spread to South America, and endemic North American wolves, Canis edwardii and the putative red wolf evolved out of an unrelated jackal-like line.

The coyote descended from some sort of jackal-like canid in North America and a least a million years of evolution separates the coyote from the modern gray wolf.

The most recent study that examined full genomes of various wolves, dogs, and coyotes revealed that the separation between coyotes and gray wolves happened only 50,000 years ago. This finding pretty much destroys all this thinking.

We’ve conventionally thought of the lineage starting out with jackal-like forms that evolve into wolf-like forms, but the truth is we have a lineage that started out with jackal-like forms. Wolf-like forms evolved at least twice from this lineage, and jackal-like forms have evolved from wolf-like forms as well.

What we’ve missed that just as the Xenocyon and the dhole and African wild dog have evolved into wolf-like forms in parallel to actual wolves, the real story of Canis is that there has been a constant tension between selection for wolf-like traits and jackal-like traits. The coyote is a wolf that has re-adapted itself to the jackal-like form. To become a jackal is to become a generalist again. To evolve towards the wolf is become an apex predator and be forced to hunt for large game to survive.

What we know from the fossil record is the story of wolves and dogs and coyotes and their kin is that it began with “jackals.”  Paleontology says that North America is where this story got started, but the oldest species in this lineage of dogs lives in Africa.

I would love to know the full story.

Canis cedazoensis is a creature lost to time. If we could see one, maybe we know some answers. Maybe we would see something very much like a black-backed jackal. Maybe it would answer some questions.

And it would probably raise more.

Yet more of the mystery to which we should humble ourselves.

It began with jackals, and in the Anthropocene, it may end with them as well. The coyote and Eurasian jackal have continued to spread their range. The coyote is from from Alaska and Newfoundland to Panama– on its way to Colombia. The Eurasian jackal (the “golden jackal,” as it is normally called) spreads north and west through Europe. Both are generalists of the jackal type.

Phenotypic plasticity and convergent evolution have played quite a game with this part of the dog family.

Science is always provisional, and often takes just one profound discovery to turn over the apple cart.

And oh, has it been turned!

 

 

 

 

 

 

 

 

 

 

 


Natural History

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