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Patterns of Prey Selection by Wolves
in Denali National Park, Alaska

by

L. David Mech, Thomas J. Meier, John W. Burch, and Layne G. Adams

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The patterns of selection by wolves (Canis lupus) preying on moose (Alces alces), caribou (Rangifer tarandus), and Dall sheep (Ovis dalli) in Denali National Park and Preserve, Alaska were studied from 1986 through early 1992. Wolves and their prey are legally protected or relatively unharvested in most of the area, and wolf numbers doubled during the study. Based on remains of 294 moose, 225 caribou, and 63 sheep, wolves killed calves and old adults disproportionately, and individuals with low marrow fat, jaw necrosis, or arthritis. Seasonal trends in proportions of various species, ages, and sex of kills were found. During the winters following winters of deep snowfalls, wolves greatly increased the proportion of caribou cows and calves taken. We conclude that in a natural system, wolves can survive on vulnerable prey even during moderate weather, and when snowfall exceeds average, they can respond by switching to newly vulnerable prey and greatly increasing their numbers.

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This resource is based on the following source (Northern Prairie Publication LDM0144):

Mech, L. David, Thomas J. Meier, John W. Burch, and Layne G. Adams.  1995.  
     Patterns of prey selection by wolves in Denali National Park, Alaska.  
     Pages 231-244 in L.D. Carbyn, S.H. Fritts, and D.R. Seip, eds.  Ecology 
     and Conservation of Wolves in a Changing World.  Proceedings of the 
     Second North American Symposium on Wolves,  Canadian Circumpolar 
     Institute, Edmonton, Alberta.  Occasional Publication 35.

This resource should be cited as:

Mech, L. David, Thomas J. Meier, John W. Burch, and Layne G. Adams.  1995.  
     Patterns of prey selection by wolves in Denali National Park, Alaska.  
     Pages 231-244 in L.D. Carbyn, S.H. Fritts, and D.R. Seip, eds.  Ecology 
     and Conservation of Wolves in a Changing World.  Proceedings of the 
     Second North American Symposium on Wolves,  Canadian Circumpolar 
     Institute, Edmonton, Alberta.  Occasional Publication 35.  
     Jamestown, ND: Northern Prairie Wildlife Research Center Online.  
     http://www.npwrc.usgs.gov/resource/mammals/denali/index.htm  
     (Version 06JUL2000).

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Table of Contents

• Introduction
• Study area
• Methods
• Results
  • Age and Sex Structure of the Kill
• Discussion
• Acknowledgements
• Literature Cited

Tables

• Table 1 -- Cumulative snowfall.
• Table 2 -- Composition of prey killed by wolves.
• Table 3 -- Frequency of wolf kills.
• Table 4 -- Percent femur marrow fat content of prey killed by wolves, October-May 1986-1991.
• Table 5 -- Percent femur marrow fat content of prey killed by wolves, October-April 1988-1992.
• Table 6 -- Incidence of skeletal abnormalities in prey killed by wolves.

Figures

• Figure 1 -- Annual proportions.
• Figure 2 -- Monthly proportions.
• Figure 3 -- Age structure of moose killed by wolves.
• Figure 4 -- Age structure of caribou killed by wolves.
• Figure 5 -- Age structure of Dall sheep killed by wolves.
• Figure 6 -- Distributions of percent marrow fat killed by wolves.

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