I reported a black wolf or dog that I saw in the range of the Mexican wolf in Arizona last year (WLJ Aug. 17, 2023). I thought it would interest government wildlife biologists because there are not supposed to be black Mexican wolves. As far as I know, they haven’t followed up on the animal’s status after I told them about it.
The Mexican wolf’s range is in Arizona and New Mexico, and there are black wolves in states to the north. If the animal is a black wolf, it likely migrated into the Mexican wolf population from the north. If the animal is a black dog, it indicates that interbreeding could occur between dogs and Mexican wolves because the animal was alone in the woods and unaccompanied by people.
The Mexican wolf is claimed to be genetically unique and an important form of wolf designated as a “subspecies.” I’ve written about subspecies before and how the rigorous scientific community recognizes that subspecies are not definitive groups. Nevertheless, the Mexican wolf mixing with dogs—or northern wolves, which are a different subspecies—is a potential management problem because of the extensive efforts to preserve the “pure” Mexican wolf.
In addition to the animal I saw in Arizona, there are reports of black wolves in the range of the Mexican wolf in New Mexico. The Catron County wildlife investigator, Jess Carey, filed a Catron County Information Investigation Report about a solid black wolf and two gray wolves he saw near Luna, NM, in December 2023. Carey is a very experienced wildlife investigator, and his professional report includes photos of the animals’ tracks.
He noted in the report the animals looked like Mexican wolves and he thinks the three animals comprised a pack. He also recalls being told of a mated pair of a female gray wolf and a male black Labrador dog with a litter of six black pups in New Mexico near Old Horse Springs in Catron County several years ago. The USDA Wildlife Services killed five of the six pups and one got away. This observation needs official verification.
These sightings suggest that immigration of black wolves from the north and/or mating of Mexican wolves and dogs has occurred. Does it matter? Not from a practical standpoint. The wolves in Arizona and New Mexico kill livestock and big game, and genetics from northern wolves or dogs won’t change that.
It matters from a legal and regulation standpoint because the Mexican wolf is on the Endangered Species Act (ESA) list as a genetically unique subspecies and interbreeding with other wolves or dogs will change the Mexican wolf population’s genetics. Environmentalists want to keep the native genetics intact, even though the native genetics are largely unknown because the current Mexican wolf population originated from only seven animals.
The Mexican wolf had inbreeding problems, and the government instituted a breeding program that reduced inbreeding depression. Some recent science shows an interesting perspective regarding inbreeding and immigration of northern wolves (See the References). On one hand, northern wolves interbreeding with Mexican wolves will reduce inbreeding and increase heterosis. This is the same effect that results from crossbreeding livestock. On the other hand, interbreeding with northern wolves will change the native Mexican wolf genetics.
The introduction of northern wolves to Colorado in December 2023 makes immigration of northern wolves into Mexican wolf range more likely because Colorado borders Arizona and New Mexico. The U.S. Fish and Wildlife Service acknowledges this in the Environmental Impact Statement (EIS) for introducing wolves to Colorado. They write in the EIS that they will work with the states to prevent the northern wolves from migrating to the range of Mexican wolves to preserve their genetic integrity, meaning their native genetics. It is not clear how they will do this.
As I mentioned, northern wolf genetics will increase the Mexican wolf population’s genetic fitness with heterosis. This is indicated from studies of a coat color gene, called the K-gene which has two forms, the dominant K for black color and recessive k for gray color (see the Hedrick et al. 2016 paper in the References). Wolves and dogs with a KK or Kk genotype are black and kk are gray.
It’s similar to the dominant black and recessive red forms of the Angus coat color gene and the dominant polled and recessive horned gene in cattle. The Kk wolves show higher fitness, including better resistance to canine distemper, than the KK or kk wolves. There are currently no black Mexican wolves (except as suggested by the observations noted above), so bringing the K gene into the population would probably increase the Mexican wolf population’s fitness.
People will have different opinions on the conflicting management objectives of maintaining the native genetics or increasing genetic fitness of the Mexican wolf. However, this issue demonstrates the problems with the ESA allowing listing of subspecies, and not only entire species as the law intended. Recall that the northern spotted owl is also a subspecies. The wolf genetics issues are also largely irrelevant to the most important management objective of protecting livestock and pets from predation by wolves, whatever their genetics. — Dr. Matt Cronin
(Matthew Cronin was a research professor at the University of Alaska and is now at Northwest Biology Company LLC [www.northwestbiology.com] in Bozeman, MT. He can be reached at croninm@aol.com.)
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