Levin: Coyote Genome
It’s the beginning of mating season for the coyotes that share our valley. And when they howl from the valley rim, my dogs reply - as if they recognize a relative and their response is visceral. When I moved north, in 1975, eastern coyotes were called “coydogs,” a reference to their supposed bloodline. But a decade earlier, a New Hampshire wildlife biologist had determined that a cross between a coyote and a dog most often results in familial disaster. In late fall, when female dogs come into heat, even though food is scarce, mother dogs won’t allow their coyote mates to help rear the pups. And then in late winter, when female coyotes breed, the dog fathers abandon their mates, making it almost impossible for mother coyotes to both hunt and nurse.
And to complicate genetic matters further, during their eastward march out of the prairies a hundred years ago, coyotes occasionally crossed with lone wolves somewhere north of the Great Lakes.
So when eastern coyotes arrived here in the nineteen forties, they were larger, faster, and more ravenous than their western cousins. Because venison accounts for one third of their diet, coyotes may have replaced automobiles as the principle deer predator in the Northeast.
Eastern coyotes, which weigh up to seventy pounds, may be mistakenly called “coywolves,” another simplification of their pedigree. According to sophisticated DNA analysis, Vermont coyotes are a “hybrid swarm,” a potpourri of both the wild and the not so wild.
One recent genome study determined the ancestry of the average eastern coyote is 64% western coyote, 26% wolf, and 10% dog … a sort of canine chimera. Farther south, the mixture changes. In Virginia, coyotes average 13% dog and 2% wolf. In Florida, coyotes are mostly coyotes with just a smattering of dog and wolf.
And there’s more. Some mammalogists believe that North America supports two species of gray wolf, a western and an eastern species, and that a third species, the so-called red wolf of the Southeast, is merely a blend of gray wolf and coyote – and the dark coat of some North American wolves may be an artifact of crossbreeding with the dogs that accompanied the first humans into the New World.
This canine mélange suggests that the biologic definition of a species, which once leaned heavily on reproductive isolation, is shifting. After all, every botanist knows that hybridization is a natural and recurring theme in plant evolution. And even humans are now thought to be the product of an inter-species tryst.