All wolves in North America, from those found in the arctic tundra, to those living in the southern U.S., are considered by biologists to be grey wolves. They have always believed that environmental adaptation was the cause of the varying shades of grey found among wolf populations.
Genetic Research on Black Wolves
Now, however, a study by Marco Musiani from the University of Calgary and Gregory S. Barsh of Stanford University, has found that the occasional black wolf that occurs in grey wolf packs carries a colour gene inherited from domestic dogs. The study, published in the academic magazine Science, states black wolves are much more common in forested areas than on the tundra, but the black coat has little to do with camouflage. In a February 5, 2009 Associated Press article by Randolph E. Schmid entitled “Researchers Say Black Wolves Inherited their Colour from Ancient Dogs,” Barsh agrees that the camouflage idea is appealing, but notes that wolves are the top predators, and don’t have many predators themselves, so they have little use for concealment. Secondly, the researchers noticed that black wolves grey with age, much like humans and dogs do. If “…the black coat-colour mutation was being selected because it caused the black coat colour, you wouldn’t get these older grey wolves, they would stay black,” said Barsh in the interview.
Genetic testing of black wolves has shown that the dominant gene responsible for black coats is the same as that found in black poodles and labradors. Though dogs were domesticated from wolves between 15,000 and 30,000 years ago, the black-coat gene was probably passed back to wolves between 10,000 and 14,000 years ago when humans crossed the land bridge over the Bering Strait.
Advantage to Black Wolves
Black coats could actually prove to be an advantage in the future suggests Marco Musiani. In a February 6, 2009 UToday online interview, he stated: “I have spent a lot of time in tree-line areas at the southern edge of the tundra and it has always surprised me that there are white wolves and black wolves but no gray wolves in these areas.” He surmises that with the environmental changes caused by global warming, such as the northern expansion of the boreal forest, black colouration may help grey wolves adapt to new conditions. “…Wolf populations are quickly adapting to conditions with less snow by taking advantage of the human-created shortcut of black coloration.” (See first link.)
Though black coats in wolves have been human-induced, they could prove to be an evolutionary advantage as snow packs shrink and grey wolves become more noticeable to potential prey on the darker ground. Better hunting success means better survival rates for black wolves. What remains to be answered is the question of the future of grey wolves.
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