It remains to be seen whether some of the more recent lower densities of wolves will help reduce the frequency and extent of any future outbreaks within the park. In addition to CDV, there is another parasite that has had measurable impacts on wolves in Yellowstone: the microscopic mite, Sarcoptes scabiei. Introduced as part of predator-eradication efforts in the early 1900s, sarcoptic mange presumably persisted among other furbearing species until reappearing within Yellowstone packs in 2007. The mite burrows into its host’s skin, where it causes the infected individual to scratch itself to the point of hair loss (figure 2). These hairless lesions can result in an estimated doubling of energy expenditure to keep warm during winter months (figure 3), decreased body condition, and an increased risk of mortality.