Conservation Corner: Two days conducting dental examinations on whitetail deer
The week after Thanksgiving brings a noticeable change to the landscape of rural Ohio. Fields and woods that have put on their drab colors of winter are suddenly splashed with a flurry of blaze orange as hunters clad in garments of this neon hue partake in the statewide firearm season targeting whitetail deer.
Tens of thousands of the state’s largest game animal will be harvested during this week-long period which, along with providing an economic boom to retailers and meat processors, gives Ohio Division of Wildlife research staff a chance to collect a multitude of data that may include the age and sex of harvested deer, hunter surveys, or tissue samples for disease monitoring. Over the years I have participated in many of those duties, but the one that seems to garner the most discussion is when we set up shop at a local processor on Monday and Tuesday and record the age of any dropped off deer before they become venison steaks, burger, or jerky.
Determining the age of wild animals can involve some interesting techniques. Sometime this can be done while the animal is still alive, but often requires a more invasive approach that is best performed post-mortem. Whether it’s looking at molt patterns on bird feathers, instar stages of insects, or growth rings on tiny, bone-like structures found in a fish’s head, the information gleaned doesn’t usually provide an exact birth date and almost always requires a bit of subjective interpretation by the data collector. Aging whitetail deer is no different.
Despite many claims that antler size, hair color, or body mass can be used to accurately assess a deer’s age, the most dependable method involves peering into the animal’s mouth and taking a look at its teeth. Deer, like humans and other mammals, have teeth that erupt at various life stages and have some “baby” teeth that are replaced by a permanent set along the way. Whitetail deer also have a reproductive strategy where nearly all offspring are born during a several week period during the latter part of May and early June. This means that deer harvested during the annual Ohio firearm season are assumed to be some variation of a year and six months in age. Young of the year will be six months old while older generations will be one-and-a-half, two-and-a-half, three-and-a-half, and so on.
Thanks to previous studies and research on deer dentition, we know that six-month-old deer will only have a combination of three premolars and a single molar visible in each lower jawbone. The three premolars are considered its baby teeth and will be replaced in the future. By the time the deer gets to be one-and-a-half years old, aka a “yearling,” two additional molars will have emerged behind the original four bringing the total per jaw up to six. At this point, the deer has reached its maximum tooth occupancy, but can be separated from older individuals because it still retains three temporary premolars. Because variation will always exist in the natural world, however, some deer may replace their premolars early which can lead to some confusion. Thankfully, since deer aren’t known for regular brushing and flossing, the newly replaced teeth are often noticeably cleaner than the adjacent permanent teeth and this helps determining when you’re dealing with a yearling that’s just slightly ahead on its tooth replacement schedule.
At two-and-a-half years old, the deer will have completely replaced the three premolars and have a full set of permanent teeth that generally show equal staining or discoloration across all six teeth. In a data collection setting, deer can be accurately and objectively aged into three age groups: six months; eighteen months; and two-and-a-half years or older. Using the Division of Wildlife’s methodology, female deer are cataloged based on these basic criteria. For bucks however, the personnel aging deer are tasked with using some further investigative techniques to interpret wear patterns of the enamel and dentin and give a more detailed estimate on the age beyond two-and-a-half. At this point, the aging becomes a little more subjective and can be further complicated because teeth wear at different rates based on the deer’s diet. Deer grazing on hay and munching corn and soybeans in the agricultural regions will present differently than those in the hills feeding primarily on hard nuts and woody browse, but overall, an educated guess can be made in most cases.
So, if you happen to be visiting your local butcher and see me or another wildlife employee prying open and peeking into a whitetail’s mouth, know we’re not budding deer dentists – we’re just figuring out how many birthdays it has celebrated.
Tommy Springer is the wildlife and education specialist for the Fairfield Soil and Water Conservation District. He can be reached at 740-653-8154 or at Tommy.Springer@fairfieldswcd.org
This article originally appeared on Lancaster Eagle-Gazette: Conservation Corner: Two days conducting dental examinations on whitetail deer
