What killed this White-tailed Deer?


We received a report from several people about a fresh white-tailed deer carcass in Pine Island on Wednesday March 2, 2011.  The body was slightly warm and the limbs were starting to get stiff with rigor-mortis.  There were a couple differences about this animal that made me wonder how the animal had died.  The first thing that intrigued me was that it was located about 50 feet north of Bissell Rd., so I wondered if this animal was struck by a car and walked a short distance into the woods and died.  The other odd thing is that the animal died right in the center of the Mattatuck Trail with no obvious signs of struggle.  Deer and other wildlife frequently use the human trails to travel when the snow is deep because the snow is compacted on the trail and it is easier to walk on.  However, I did not observe any tracks or sign in close proximity of the carcass that indicated a predator could have killed the animal.  The animal's hind quarters were injured, which may suggest a coyote had attacked it before and it died some time after.  But these injuries could have been caused by scavengers because there was not a large amount of blood lost on the snow near the injury.  American crows were observed scavenging the animal on other body parts.  There were no other external injuries that suggested it was hurt by a vehicle.  So, why and how did animal die? Was it hit on the road by a vehicle? Did a predator injure it, which lead to its death?  Did this animal die because it was an extreme winter and it died from exposure?  The scavengers were already working on the carcass and I had to make a fast decision.  I decided to do a quick necropsy to see what clues I could find.  Check back for future blog entries this week to learn what I discovered.

White-tailed deer carcass after I performed a quick necropsy
to examine what may have caused it death.
Photo By James Fischer
Next Blog Entry:

What killed this White-tailed Deer? Part 2: Sex Determination and Tooth Wear Pattern

Advisory:  Please do not touch, feed, or disturb wild animals of unknown origin.  If you see an animal in distress please contact a licensed animal control officer, licensed wildlife rehabilitator, or other trained and certified wildlife professional.  You may expose yourself or the animal to unnecessary injury, distress, or disease.  This procedure was performed by a professional wildlife biologist who took proper precautions to avoid exposure to pathogens and other potential human-wildlife diseases.


rkling said...

I wonder what pathogens or other potential human-wildlife diseases would be present and how does the hunter and the subsequent butcher reduce danger of such?
Bob Kling

James Fischer said...

Great question! Bob,

Since I was not sure how this animal died, I needed to be more cautious of potential pathogens. White-tailed deer are mammals, as well as humans, so there are several potential pathogens that can be transmitted to humans from white-tailed deer (i.e. rabies and others). The first thing that a biologist needs to consider when performing a field necropsy is to be aware of all sources of mortality in the population. Fortunately, wildlife biologists in this area are keeping a close eye open for the emergence of Chronic Wasting Disease, which currently is not known to affect humans who contact or consume infected animals. I have examined several deer carcasses in various stages of decomposition or after scavengers consumed large portions of the carcass. This carcass provided us with a unique opportunity to examine several tissues. I initiated this procedure having a couple hypotheses about what could have caused the mortality of the animal. I wore protective gloves during this procedure. Unfortunately, I did not take samples of organs or fluids that would allow us to pursue a more thorough examination. Because the lab fees are too expensive to perform when we have not observed any other signs in the population to be alarmed at this time.

Hunters and butchers know what caused the mortality of the animals they work with, nevertheless there are some potential pathogens that can be infectious to those who come into contact with infected animals. Therefore, hunters are advised to wear protective gloves and are trained through the mandatory "Conservation Education and Firearm Safety" course that is offered for free by CT DEP, Wildlife Division. I believe, but do not know for sure, that butchers are required to wear protective gloves and clothing to comply with work safety standards.

Thanks for question, Bob, feel free to write back if need more information.

James Fischer