One black-tail deer tooth tells quite a story — let’s learn it together

Was that big-bodied 3-point buck you harvested last year three or four years old? What about that gray-faced 5-point buck your daughter tagged a few years back?

You can make a guess based on the number of antler points, especially for those spike (1-point) bucks (they’re usually yearlings), or by looking at the number and wear of the teeth. Hunters often combine information on antlers, size, and coloration to come pretty close.

But, one surefire way to find out the animal’s age is through a process called cementum analysis. As an animal ages, its teeth grow layers of cementum, a thin layer of material that helps cement roots in the gums. Biologists can actually count these layers like tree rings to estimate age.

We at the Washington Department of Fish and Wildlife are just as interested in the age of harvested black-tailed bucks as Washington hunters are, and last year we asked hunters to submit black-tail buck deer teeth for a new study.

The main premise of the study is to see how the number of antler points relate to age. The more we understand that relationship the more information we can get about a population’s age structure. The data may even allow us to someday use hunter harvest reports to estimate how many animals are in a population.

In 2019, hunters submitted 473 teeth, and we’ve aged most of them. Naturally you might expect that the older a buck is, the more antler points he has. In some cases, the data we received from black-tail deer hunters supports that guess.

For example, a spike buck is one year old 83% of the time, based on our 2019 sample.

Did you harvest a buck with a maximum of 2-points on either side? Well it’s most likely two or three years old — 41% and 26% of our 2019 sample, respectively.

A similar pattern of increasing age with increasing antler points continues, yet we see some age variability as antler points increase.

Black-tailed deer buck age plotted by maximum antler points (side by side comparison). Data points are weighted by proportional values (larger circles equal larger values), calculated per antler point category (i.e., proportions sum to 100 by antler point category). For example, 83% of reported spike bucks were one year old, 9% were two years old, and 8% were three years old.

That variability is natural and expected — antler shape and size are a function of not only age but also nutrition and genetics. But we also know that our sample size is small, especially for higher antler point categories. So, we’re asking for more teeth this year to add to the data.

A larger sample size will help us determine if using antler points is an appropriate measure to catalog a buck’s age at harvest. If so, we might be able to use information from hunter reports, like hunter effort, along with other data, like survival rates from radio collar tracking, to estimate the black-tailed deer population through a process called statistical population reconstruction.

So, if you harvest a black-tailed buck this season — whether it’s a 5x5 you’ll tell the grandkids about or a respectable meat-in-the-freezer 2x2 — we hope you’ll participate in the study and send us a tooth. Follow the link to the form to submit a tooth. Watch this video to learn how to extract a deer tooth and check out the image below for an illustration of which tooth to extract.

About six months after you send us a tooth, you’ll be able to confirm the age of your harvested buck using WDFW’s Tooth Age Lookup page. And don’t forget to fill out your harvest report!