Is this deer sick?

Our Snapshot Wisconsin trail cameras capture images from all over the state and throughout the year.  Sometimes folks spot a critter that looks a bit different from the others and ask, “Is this deer sick?”  In most cases, the answer is “not likely.”  In this post we are sharing some of our most frequently asked questions about deer appearance and wildlife diseases.

M2E28L65-65R387B337This deer looks skinny!  Is it sick?  Could it have CWD? 

Winter in Wisconsin can be quite rough for a deer!  In summer food sources are abundant, but come wintertime deer have to rely on less nutritious forage like twigs, lichens, or leftovers in harvested crop fields. Because resources vary significantly with the season, a deer’s weight will also vary.  After particularly long winters, deer may look very skinny the following spring and even in to early summer.  But not to worry; they will put the weight back on in no time.

CWD (chronic wasting disease) is a fatal nervous system disease that affects deer, elk, and moose.  CWD has been found in wild deer in 23 Wisconsin counties, with highest prevalence in the southern part of the state. Clinical signs of CWD include diminished muscle tone and emaciation, but outward symptoms often do not appear for months or years after infection. The disease is best confirmed through a lab test for the disease; physical appearance based on trail camera images is not a reliable indicator.  More likely a deer is skinny because of poor food resources in winter and not because of CWD or some other disease.


What is wrong with this deer’s coat? 

Each spring deer molt or lose their winter coats.  The thick grey hairs that make up the winter coat are replaced with a new reddish-brown summer coat.  This molting process can happen quite quickly and during the transition deer can look a little ratty and rough.  This is a normal process and nature’s way of making sure deer are “dressed” for the temperature.

M2E52L150-149R399B383This deer has an injury.  Can you notify someone or help this deer?

Sometimes deer with physical injuries show up in our photos.  This is common for wild animals. These injuries can be caused by any number of reasons, such as scraping against a fence or perhaps from a predator.  In many cases, the small injuries will heal quickly, leaving a scar or patch bare of hair.  In cases where the injury is major (say from a car collision) and the deer cannot recover, the animal will become an important food source for scavengers.

All of the photos appear on Zooniverse many months after they have been taken, and the animal may no longer be in the area.  Although reporting the observation via Zooniverse will not be helpful, Wisconsinites who personally observe sick or dead animals can make a timely report to their local DNR office or contact a licensed wildlife rehabilitator.


About Christine Anhalt-Depies

Graduate Student at the University of Wisconsin-Madison. Follow me on Twitter @anhalt_depies.

2 responses to “Is this deer sick?”

  1. Sabina Fairbrother says :

    Answering these questions so fully here, along with photos is a great idea and provides a useful resource.


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