Before wolves were reintroduced to Yellowstone National Park in the mid-1990s, they were vaccinated for common diseases and treated for any parasite infections they already carried. As a result, the first few generations of wolves were relatively disease-free, but over the years, various diseases – including mange – have found their way into the population.

Little is known about what causes the variation in manginess, but a team of researchers, led by then-Princeton graduate student Alexandra DeCandia, sought to uncover this mystery. Their study, published in Evolutionary Applications, brings together schools of thought from molecular biology, disease ecology and conservation biology.