Day 17: Wolves of all stripes

Displaying distinct coat color phenotypes, these two wolf pups from Yellowstone National Park's Agate Creek pack were born in the same litter resulting from the pairing of a black female with a gray male. Image courtesy of Daniel Stahler/NPS

At first, last week’s announcement that black coats in wolves come from interbreeding with dogs didn’t interest me that much. I have a long-time fondness for wolves, and I don’t particularly care what color they are. But from a gee-whiz biology perspective, the finding actually is pretty interesting. Also, the news was a chance to take a trip down memory lane, and check in on the very first environmental issue that I truly cared about: wolf reintroduction. It’s nice to learn that wolves are getting along all right in some parts of the country. Still, too many wolves are getting shot.

First, the science.

Tovi Anderson, a genetics graduate student in Stanford University’s School of Medicine, is lead author on the study, published in Science last week. Anderson and her team analyzed DNA from 150 Yellowstone National Park wolves. They found that a novel gene variant from dogs is responsible for black coat color and was transferred to wolves through mating.

The biologists believe the gene transfer couldn’t have occurred within the past several hundred years; the black coat is too widespread. They suspect wolves mingled with dogs that lived among Native Americans, before Europeans arrived. Study co-author Robert Wayne, an ecologist and evolutionary biologist at the University of California in Los Angeles, said the study marks the first example of a gene mutation originating in a domesticated animal and then taking off in a closely related wild species.

“No one would have guessed that the common black coat color in North American wolves came from dogs — there is no precedent for it,” he said. “Moreover, for whatever reason, the transfer of the black coat-color gene from dogs to wolves and its success in the wild occurred uniquely in North America.”

Scientists have speculated that coat color is related to camouflage, perhaps to hide wolves from their prey or from one another. The research team is planning further inquiries to determine whether the black coat color provides a fitness or behavioral advantage to wolves in the wild.

Okay, so … how are wolves faring these days? When I was an undergrad in the mid-1990s and just discovering Barry Lopez, biologists in North Carolina were trying to reintroduce red wolves in both coastal and mountainous regions of the state. Especially in the coastal regions, the wolves didn’t seem to be adjusting very well. The program took off slowly, in fits and starts. Meanwhile, efforts to reintroduce gray wolves in the American West were just just a few years ahead; mostly, federal biologists were attending public meetings to show educational wolf videos to ranchers who were wary — and opposed. At that time a third effort, to reintroduce Mexican wolves in Arizona and New Mexico, was an apple in some biologist’s eye.

Today, the conservation group Defenders of Wildlife calls North Carolina’s red wolf reintroduction program “a biological success” with about 100 red wolves in the wild, but continues to work with the U.S. Fish and Wildlife Service to ensure the animals’ survival. The biggest risk is apparently the wolves’ sexual attraction to coyotes, which threatens to dilute their genome.

But, hundreds of years after their alleged escapades with domestic dogs, gray wolves (and their black relations) have rebounded. According to Defenders of Wildlife, nearly 1,200 wolves are alive and well in the greater Yellowstone area, northwest Montana and central Idaho. Defenders expressed alarm when former President Bush tried to have the wolves removed from the Endangered Species List in his final days of office. They feared the wolf population would plummet in the face of unrestricted hunting that could follow. For now, the Obama administration has put the delisting on hold.

The Mexican wolves are having the hardest time. Although the U.S. Fish and Wildlife Service and its partners expected to achieve 100 free-roaming wolves by 2007, the number hasn’t reach half that — and it’s 2009. Fifty-two Mexican wolves were counted in the wild in Arizona and New Mexico at the end of 2008, the very same number recorded in the 2007 survey.  Illegal shooting was the leading cause of documented loss of wolves in 2008, with seven wolves falling victim to “illegal shooting or suspicious demise,” according to a Fish and Wildlife press release issued over the weekend.

My hope for all the wolves is that — red, gray or black — they’re increasingly carrying a stealth gene to help them escape from the “shoot, shovel and shutup” gene that’s evidently lurking in human DNA. That is to say, I hope there is a certain number of wolves that never get counted in the surveys.