Scientists have long been puzzled by the fact that, across the North American continent, wolves tend to change their coat color
While in the Arctic Canada and other northern areas wolves tend to be grey, in the south, most of them are black.
Now, a team of researchers led by the University of Oxford has found that patterns of infectious diseases can drive coat coloring in wolf populations.
Coat color in wolves is determined by a gene called CPD103: depending on the variant of this gene that a specific wolf has, its coat can be either grey or black.
By examining 12 wolf populations in North America, the scientists found that this gene also plays a major role in protecting against respiratory diseases such as the canine distemper virus disease.
The analyses revealed that most of the black wolves had CDV antibodies (suggesting that they contracted the disease in the past and survived)
That this coloring was more frequent in areas where CDV outbreaks occurred.
Thus, black wolves appeared to be more likely to survive CDV outbreaks compared to grey wolves.
By analyzing 20 years-worth of data from the wolf population at the Yellowstone National Park, the scientists found that
In areas where CDV outbreaks occur, wolves would often choose mates of the opposite color in order to maximize the chance that their cubs would have black coats.
According to the scientists, other animal species – such as insects, amphibians, birds, and some non-human mammals
May also have evolved associations between color patterns and disease resistance, leading them to conclude that the presence of a disease
The frequency of disease outbreaks, are major factors affecting the color of mate an animal prefers.