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Wolves & White-Tailed Deer: Co-Existence

The relationship between wolf and deer populations is complicated and dynamic, dependent on factors like the density of both species, the presence and abundance of other prey species, winter severity, and human activities.

Some people worry that wolves have a detrimental impact on the size of the wild deer herd. Except in a few specific situations wolves have not, by themselves, caused significant declines in deer populations. To blame just the wolf is to disregard the complexities of the natural world. It is important to remember that wolves and deer have co-evolved to their modern form for at least the past one million years, molding each other's behaviors and physical characteristics into their current state of co-existence.

• Wolves can kill any deer under the right circumstances, not just the sick and the weak as once thought. But as all predators, wolves usually prey upon the most vulnerable or available animals.
  
  
• Wolf predation on deer is greatest during mid to late winter when deer have been weakened by cold temperatures and deep snow. Wolves prey upon newly-born fawns encountered during June and July. It has been noted that black bear can have more of an impact on deer fawns in the UP Michigan than wolves. These are the same seasons of the year when other forms of natural mortality take their greatest toll on the deer population.
  
  
• Wolves may have some impact on isolated deer populations (most often in island situations) but only when wolf densities are greater than one wolf per10 square miles and deer densities are less than 4 deer per square mile.
  
  
• Winter severity has more of an impact on deer than wolves.
  
  
• To compare wolf depredation on deer with other forms of deer mortality:
  • 3,000 estimated wolf population of the Upper Great Lakes region
    
  • 60,000 estimated number of deer taken by these wolves annually
    
  • 300,000+ estimated number of deer starved to death during the severe winter of 1995-96 in Michigan's Upper Peninsula and Wisconsin
    
  • 1,270,000 total estimated number of deer from all seasons taken by hunters in Minnesota, Michigan, and Wisconsin in 2003 (Numbers are from the Minnesota, Michigan, and Wisconsin Departments of Natural Resources)
    
  • 104,000 total estimated number of deer killed by vehicles in Minnesota, Michigan, and Wisconsin in 2000