Effects of Sarcoptic Mange on Gray Wolves in Yellowstone National Park.
Funding Sources: USGS-NPS POBS funding; Collaborators: Doug Smith - Yellowstone National Park Wolf Project, Adam Munn, Peter Hudson, Andy Dobson, John Heine - Grizzly and Wolf Discovery Center.
Sarcoptic mange is a highly contagious canine skin disease caused by mites that burrow into the skin causing infections, hair loss, severe irritation and an insatiable desire to scratch. The resulting hair loss and depressed vigor of an infected animal leaves them vulnerable to hypothermia, malnutrition and dehydration, which can eventually lead to death. Mange was introduced into the Northern Rockies in 1909 by state wildlife veterinarians in an attempt to help eradicate local wolf and coyote populations. Scientists believe the troublesome mite that causes the disease persisted among coyotes and foxes after wolves were exterminated. Since their reintroduction into the Greater Yellowstone Ecosystem in 1995-96, wolves appeared to be free of mange until 2002. As of November 2012, 4 of 8 known packs in Yellowstone National Park (YNP) have mange, mostly in the Northern Range and the prevalence within a pack ranges from 30 to 80%.
Wolves are a popular feature for the public visiting YNP and as a result mange in wolves is likely to become a topic of visitor interest. At present limited information is available on the impacts of mange in wolves at both the individual and population levels. We are examining the impacts of sarcoptic mange on the survival, reproduction and social behavior of YNP wolves, as well as document the progression of infection and associated host recovery rates. This project is providing technical assistance to YNP and simultaneously exploring an emerging issue, providing a foundation for future long-term monitoring that will be useful to state and federal management of wolves in the Montana, Wyoming, and Idaho wolf recovery areas.
To help understand the role of mange in the lives of gray wolves, researchers need to understand the costs and extent of infection. Thermal imagery of wolves allows scientists to not only document the extent of hair loss caused by mange, but the actual loss of heat associated with the different stages of infection.
Researchers at NOROCK and their partners are using thermal cameras at the Grizzly and Wolf Discovery Center in Montana to assess the amount of heat lost under a range of environmental conditions with and without hair. In this image, brighter areas are giving of more heat.
To simulate hairloss that occurs in the later stages of mange infection, patches are shaved on the wolves (red spot on hind leg) to allow the researchers to measure temperature loss from the hairless patches and compare this with temperature loss from natural fur. By helping out with this research the wolves in the enclosure are helping scientists better understand how mange operates in their wild counterparts throughout the Greater Yellowstone Ecosystem.
All research animals are handled by following the specific requirements of USGS Animal Care and Use policies.
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Almberg, E.S., P.C. Cross, A.P. Dobson, D.W. Smith and P.J. Hudson. 2012. Parasite invasion following host reintroduction: a case of Yellowstone’s wolves. Philosophical Transactions of the Royal Society. 367, 2840-2851. doi: 10.1098/rstb.2011.0369.
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