(KPAX) YELLOWSTONE NATIONAL PARK — The black wolves of Yellowstone are a striking icon that draws many wildlife watchers to the world’s first national park.

But scientists say historically wolves did not have black coats. Cutting-edge science is now revealing the secret behind the origin of the black wolf.

“Black wolves are throughout the Rocky Mountains in the United States and up into Canada,” Dr. Dan Stahler, a Yellowstone National Park wildlife biologist said recently in a park presentation on wolves.

“As you get farther north you get into more white, Arctic wolves. Then in the central part, in the Great Lakes states, you have more gray wolves and very few black wolves.”

Stahler said things like camouflage, behavior, finding mates and thermo-regulation are key factors in determining the color of a wolf.

He said genetics show the original wolf color, and “we noticed that our wolf packs that had two gray breeding pairs, could only produce gray offspring.”

So where did black wolves come from? Stahler says you can thank humans and our pets for adding black to the color palette for wolves.

“Humans bringing domestic dogs across about 7,000 years ago brought these dogs that had black coat color genes in them,” he said. “And some of these dogs bred with wild wolves, somewhere in the area of the Yukon. And this gene got into wild wolf populations.”

That gene was found when cutting-edge technology was used to sequence the genome of Yellowstone wolves. The gene isn’t just for color.

It also gives black wolves a stronger immune system. But Stahler said gray wolves also have a secret genetic advantage.

“We found that gray-colored female wolves had higher litter success, survival of their pups, than black-colored wolves,” said Stahler.

According to Stahler, that’s why no one color is dominant. Yellowstone wolves are split 50-50 by color. But the black ones owe 100% of their color, to humans, and our dogs.

You can find Stahler’s entire presentation on the genetics of wolves on the Yellowstone National Park Facebook page.