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Wolf-Bison Interactions in Yellowstone National Park

Douglas W. Smith*, L. David Mech, Mary Meagher, Wendy E. Clark,
Rosemary Jaffe, Michael K. Phillips, and John A. Mack


We studied interactions of reintroduced wolves (Canis lupus) with bison (Bison bison) in Yellowstone National Park. Only 2 of 41 wolves in this study had been exposed to bison before their translocation. Wolves were more successful killing elk (Cervus elaphus) than bison, and elk were more abundant than bison, so elk were the primary prey of wolves. Except for a lone emaciated bison calf killed by 8 1-year-old wolves 21 days after their release, the 1st documented kill occurred 25 months after wolves were released. Fourteen bison kills were documented from April 1995 through March 1999. All kills were made in late winter when bison were vulnerable because of poor condition or of bison that were injured or young. Wolves learned to kill bison and killed more bison where elk were absent or scarce. We predict that wolves that have learned to kill bison will kill them more regularly, at least in spring. The results of this study indicate how adaptable wolves are at killing prey species new to them.

Key words: Bison bison, Canis lupus, Cervus elaphus, mortality, predation, restoration, wolf, Yellowstone National Park


This resource is based on the following source (Northern Prairie Publication 1266):
Smith, Douglas W., L. David Mech, Mary Meagher, Wendy E. Clark, Rosemary Jaffe, 
     Michael K. Phillips, and John A. Mack.  2000.  Wolf-bison interactions in 
     Yellowstone National Park.  Journal of Mammalogy 81(4):1128-1135.

This resource should be cited as:

Smith, Douglas W., L. David Mech, Mary Meagher, Wendy E. Clark, Rosemary Jaffe, 
     Michael K. Phillips, and John A. Mack.  2000.  Wolf-bison interactions in 
     Yellowstone National Park.  Journal of Mammalogy 81(4):1128-1135.  
     Jamestown, ND: Northern Prairie Wildlife Research Center Online.  
     http://www.npwrc.usgs.gov/resource/mammals/wlfbison/index.htm  
     (Version 10JUL2001).

Table of Contents

Tables and Figures


Douglas W. Smith, Wendy E. Clark, Michael K Phillips, and John A. Mack, Yellowstone Center for Resources, P.O. Box 168, Yellowstone National Park, WY 82190; Present address for Michael K. Phillips: Turner Endangered Species Fund, Bozeman, MT 59807
L. David Mech, Biological Resources Division, United States Geological Survey, Northern Prairie Wildlife Research Center, 8711-37th Street SE, Jamestown, ND 58401; Present address: North Central Research Station, 1992 Folwell Avenue, St. Paul, MN 55108
Mary Meagher, 634 Cinnabar Road, Gardiner, MT 59030
Rosemary Jaffe, Montana State University, Biology Department, Bozeman, MT 59807
* Correspondent: doug_smith@nps.gov
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