Read more: http://www.wired.com/wiredscience/2012/05/st_photo_wolves/The wolf population in Yellowstone National Park is facing a vicious new predator: sarcoptic mange. It’s a form of scabies that causes canines to lose their hair, which translates into lost calories as the body tries to keep itself warm with holes in its shaggy coat. “If the wolves can’t replace the calories they lose, they die,” says Paul Cross, a disease ecologist at the Northern Rocky Mountain Science Center.
Scientists don’t know how to halt mange, and they don’t even know the full impact of the disease on the wolf population.”
I found the comments slightly more informative than the article itself, so I would recommend taking a look at those as well. [although some aren't of the most noble quality, but I think we can all overlook that.]