The gray wolf population in Yellowstone National Park is declining .. wolves are killing each other at a higher frequency to compete for elk, their primary food source, which is less abundant now .. mange, canine distemper and parvovirus are partly responsible, but it's the misguided legal hunts that have been carried on outside of park boundaries that have been the most devastating .. wolves can't read the signs saying that they are leaving the protection of the park and are easy victims .. wolves are not like coyotes, they don’t tolerate rapid change well, especially when there are wolf hunts