News‎ > ‎

Research Links Wolf Color to Survival and Reproduction

posted Apr 9, 2019, 8:20 PM by chloe owens

10/17/2018, by Bay Stephens, Explore Big Sky

Research links wolf color to survival and reproduction

Ongoing research in Yellowstone is revealing a curious relationship between a wolf’s coat color and its health. Preliminary studies with CRISPR technology—a tool for editing genomes—shows that something different is going on when a black wolf is exposed to canine distemper versus one that is gray. Through a partnership with the University of California, Los Angeles, biologists from Yellowstone National Park developed cell cultures derived from skin swabs from the ears of wild Yellowstone wolves. By introducing canine distemper to the cell cultures, researchers are trying to learn how black- and gray-colored wolves respond to the disease, and though preliminary, results suggest the response could be unique to the coat color. “The mechanism might be, for example, [that the coat color gene] impacts how bacteria or viruses are binding to cellular receptors,” Stahler said. What got Stahler and others interested in this research in the first place was the realization that Yellowstone’s wolves, though they are all of the gray wolf species, are a largely balanced population of 50-percent black and 50-percent gray. “In vertebrates, pigmentation is really critical for a lot of traits—camouflage, sexual selection, thermoregulation, and even behavioral physiology,” Stahler said. Knowing how important color is, the unusually balanced color population has set the stage for studies that explore the link between genetics, fitness and selection…Biologists also found that in years following large canine distemper outbreaks, black wolves had a higher survival rate than gray wolves. Conversely, though, by studying years of reproductive history, they learned that gray females had a 25-percent greater litter survival than black females. “What we speculate may be going on here, is that there are tradeoffs,” Stahler said. “There’s a cost associated with certain gene actions. Because of this beta defensin gene, which is also causing black coat color, we think there’s some link to the immune system and mounting an immune response that plays into energetics and reproduction versus survival.”… Cassidy looked at aggression in Yellowstone’s wolves, ultimately finding that gray wolves are more likely to chase off other wolves than black individuals are. Gray wolves also have higher cortisol levels, which act on aggression and stress response, suggesting that gray wolves are in fact more aggressive than black wolves.