What killed this White-tailed Deer? Part 4: Examination of Internal Organs


The next stage of this field necropsy was to examine the internal organs.  If a vehicle collision caused its death then there could be internal bleeding, damaged organs, and broken bones.  This winter has been an extremely cold and snowy winter for Connecticut, at least the historical records suggest it.  This environment may have put more stress onto the animal and it had to use more stored energy (fat) than other typical winter environments to maintain certain bodily functions.  This animal died at the end of the winter season so the lack of fat would indicate its nutritional status.  If the animal was lacking fat deposits around certain vital organs then this would suggest that the animal was utilizing its fat resources this winter and maybe depleted them detrimentally.   

Figure 1:  White-tailed deer gastrointestinal cavity with internal organs labeled,
the presence of feces in this cavity was caused by damage to the large intestine by observer.
Photo By James Fischer 
I began by rolling the animal onto it's back and then creating an incision into the lower gastrointestinal cavity (Figure 1) .  I did not notice any damage to these organs, except for a small incision that I made into the large intestine.  When hunters remove the internal organs from the animals they harvest, they try not to cut the intestinal organs because these organs contain pathogens that could make you sick if you consume them.  Fortunately, I don't make a living as a butcher.  Notice the different diameters of the large intestine and cecum (ceacum) versus the small intestine.  Most of the stomach can not be observed in Figure 1, but it is quite large because it has multiple chambers to digest the vegetation it consumes.  The diaphragm is the muscle that separates the lower body cavity from the upper body cavity and it is the muscle that is used to expand and constrict the lungs.  You can observe the liver in this body cavity and it was not injured (Figure 2).  Some of you may be wondering what an internal injury would look like.  There would a great deal of blood in the body cavity and the organs would be difficult to distinguish because they would be covered in blood.  The organs of this animal are relatively unblemished.   

Figure 2:  White-tailed deer chest cavity with organs labeled.
Photo By James Fischer
I then opened the chest cavity to examine these organs.  The rib cage was not damaged and neither was the lung on both sides of the body (Figure 2).  

Figure 3:  An adult white-tailed deer heart is a little larger
 than the size of an adult human's fist.
Photo By:  James Fischer
The two vital organs that we use to index the nutritional status of a white-tailed deer are the heart and kidney, specifically the amount of fat layered around these two organs.  I exposed the heart, which is a little larger than  the size of adult human's fist, to find that there was some fat deposited around it (Figure 3).  The fat around the heart is really important for any individual's survival, it provides padding and insulation for a vital organ.  Without this fat, an animal would probably die.  So, it was a good thing to find some fat, but not as much as it probably had in the autumn after eating loads of acorns.  

Figure 4:  An adult white-tailed deer kidney is similar in size to a tennis ball...
Photo By James Fischer
I had to turn the animal onto it's side so that I could gain access to the kidneys, which are located along the back near the spine but in the gastrointestinal cavity.  The kidney is similar in size to a tennis ball and is kidney shaped (Figures 4 & 5).  

Figure 5: ...and is kidney shaped.
Photo By James Fischer
I observed a little bit of fat around the kidneys (Figure 4 & 5), but like the heart, there was probably more in the autumn after a diet rich in nuts and fruits.    

Next time, I'll show you another organ in a white-tailed deer's body that we can observe to indicate it's nutritional status and it is not it's stomach!
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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.

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