What killed this White-tailed Deer? Part 3: Age Determination by Tooth Wear Pattern


So without further ado, what is the age of this animal?  I judged it to be almost 6 years old!  You might be saying one of two things "How?" and "Wow, thats slick!"  How did I judge this to be a 6 years old animal or a better stated question would be, what characters were use to distinguish the age?  I describe this further below.  For those of you exclaiming "Wow, thats slick!", I can't agree with you more.  It is cool that we can use tooth wear patterns to determine the age of an animal with such accuracy.  It shows that we are indeed standing on the shoulders of those who worked before us.  I would like to thank Erin Victory, Michigan DNRE Wildlife Biologist, for her corroboration.  Compared to the small number of animals that I have aged during my career, Erin has accurately assessed many more white-tailed deer jaws (in the thousands), so Thank You, Erin.  

Figure 1:  White-tailed deer mouth with additional labels numbering
 the premolars and molars, as well as some of the characters
 used for aging animal by tooth wear patterns.
Photo By: James Fischer

The characters that we use to age an animal by tooth wear are subtle and can be complicated to learn by the novice.  Therefore, I don't plan to explain every detail.  The first that caught my attention was that second and third premolars were permanent and they were quite "flat" (Figure 1).  Flat is a relative term so compare the second and third molars to the premolars, the molars are more jagged and this is similar to what "newer" teeth look like.  Now we shift our attention to the molars, particularly the first and second molars.  The letter "A" in Figure 1 points to the lingual crest of the first molar, while "B" directs your attention to lingual crest of the second molar.  Observe how this ridge is quite taller on the second molar and the ridge is shorter on the first molar.  Also notice the overall height of the first molar that is exposed above the gum line is relatively short.  I apologize that my photo does not allow you to compare this feature to the other molars, but they are relatively taller than the first molar.  Another feature to examine is the amount of brown dentine (dentyne) that is exposed on all of the molars relative to the amount of white enamel that can be observed.  You see a greater amount of  dentine than  enamel on these worn teeth, while "newer" teeth you would observe a greater amount of enamel than dentine.  There are several other characters to observe, however they are challenging to learn without a accompanying image.  So, there you have it, a challenge to learn but very useful to know and fun to practice.  

My next blog post will describe the condition of the internal organs with loads of figures!
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What killed this White-tailed Deer?

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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