Black Wolves

Descendants of black dogs

Biology News

Black wolves dominate packs in North American forests, but white wolves are more common in the treeless tundra.

Wolf distribution map (Canis lupus). Red: former range; Green: current distribution

Black wolf

"Domestication of dogs has led to dark-colored coats in wolves, which has proven to be a valuable trait for wolf populations as their arctic habitat shrinks," said study coauthor Marco Musiani, a wolf expert at the University of Calgary. "It also shows that human activities can help enrich the genetic diversity of wild animal populations, which is a very unexpected finding."

Using genetic analysis of wolf populations from North America and Europe, the researchers traced the source of the dominant gene responsible for dark coat color in wolves to domesticated dogs and concluded the trait was passed to not only wolves, but also to coyotes, by means of hybridization with domestic dogs. These hybridization events could have taken place, they say, as recently as the arrival of European dogs in North America or as long as 14,000 years ago, when humans first migrated to North America.

Since then, black fur has become common in wolf packs, perhaps because snow-covered northern regions are shrinking, and darker coloring allows for greater stealth while hunting in areas without snow. While wolves can be found in colors ranging from white to gray to black, light-coloration is predominantly found in the arctic tundra where wolves prey on caribou.

With tundra habitat expected to decline in coming years due to northward expansion of boreal forests related to global warming, the researchers note that black coloration may also help wolves survive in a changing environment.