Really, How Old is that Buck?

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Jawbone analysis is the only way to know for sure

Aging deer on the hoof is certainly possible, but tooth analysis is much more accurate. Image by Bill Konway

More than ever, deer hunters want to know the age of the animals they’re shooting. In fact, for many hunters, the question of whether a buck is “mature” or not is more important than the size of its antlers. The proof is in nationwide harvest trends. According to the National Deer Association’s latest “Deer Report,” American hunters killed just over 3 million whitetail bucks in 2020, the most in the last 21 years, and a staggering 41% of those bucks were aged 3 1/2 or older.

Deer older than 3 ½ become more difficult to age on the hoof than younger animals. There are some cues, like a blockier head and a sagging, filled-out chest, and of course, many bucks grow larger antlers with age. But none of those are sure things.

But there are some very accurate ways to age a whitetail after the deer is down. Over time, experience with that will help you compare your own estimates on live animals, and ultimately lead to more informed harvest decisions in the field.

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Pull a jawbone from each deer you harvest and gauge its age. Image by Bill Konway

Lab Results

The cementum tooth aging technique is recognized as the most scientifically accurate way to age a deer. It requires the extraction of a tooth for cementum annuli analysis. Cementum is a connective tissue surrounding the root of each tooth. Throughout the life of an animal, cementum is deposited over the root of the tooth, which forms layers that appear as rings (annuli) similar to those found in tree trunks. There is an annual pattern of cementum that causes the annuli to be visible microscopically, and thus produce an accurate age of the animal. The preferred tooth to be examined is a middle incisor, but it can still be accomplished with other teeth that are extracted properly and well cared for. Cementum annuli tooth aging is proven to be 96% accurate in blind tests.

Removing the tooth from a fresh kill is easy and can be done by cutting the gum tissue on both sides of the tooth and using the back of your knife to gently pry the tooth forward, out of the jaw. Alternatively, you can grab the tooth with pliers at the base of the tooth where it meets the gum-line, and pull firmly with a twisting motion.

You can also age animals taken in previous seasons, since labs can analyze teeth from a dried jaw. You can send in the whole jaw for an extra fee, or soak the jaw in hot water to more easily extract a tooth from an older harvest.

For $75, you can have up to five animals aged. If you have a few hunting buddies, sending off a few teeth for aging can tell you with great accuracy the age class of animals you are harvesting.

One of the nation's premier tooth aging labs is Matson’s Laboratory in Manhattan, Montana. Matson’s specializes in cementum annuli tooth aging and has a staff of experts trained on aging animals’ teeth, and they make it easy to submit teeth for aging.

Arthur Stephens of Matson’s said, “Submitting a tooth to Matson’s is as simple as extracting the preferred tooth for aging, placing in a paper envelope, filling out an order form, and packing everything up and shipping to the lab.”

For $75, you can have up to five animals aged. If you have a few hunting buddies, sending off a few teeth for aging can tell you with great accuracy the age class of animals you are harvesting. Matson’s cementum annuli aging technique works for a variety of species, including a variety of predators. In just over 50 years, Matson’s has aged 2.7 million teeth.

Fun Facts From the Matson’s Lab:

  • Oldest Whitetail Aged: 22 Years 
  • Oldest Mule Deer: 20 Years
  • Oldest Elk: 32 Years
  • Oldest Coyote: 15 Years
  • Oldest Bobcat: 23 Years
  • Oldest Grizzly Bear: 39 Years

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Keep jawbone records on the deer you shoot. Image by Mark Olis

Home Results

While not as accurate as lab analysis, you can still make a pretty good guess as to an animal’s age by studying tooth replacement and wear. The process is easier, faster, and less expensive than cementum tooth aging. All that is required to age a deer this way is counting erupted teeth and examining the tooth wear. Accurate results take serious attention to detail.

Young deer are easiest to age. Fawns only have three or four fully erupted teeth, and year-and-a-half-old deer usually have six fully present teeth along the jaw. But beyond 2 ½, deer all have the same number of teeth and to get an accurate age, you must examine tooth wear.

When examining the wear on a tooth, you’re looking for exposed dentin along the cusp of a tooth. Dentin appears brown in color, and more of it becomes exposed over the width of the tooth as a deer ages. Tooth replacement and wear is best considered alongside other factors to help estimate the age of a deer. If possible, observe trail cameras photos for body features of the deer you’re aging, and weigh the animal immediately following the kill. Taken as a whole, these cues complement one another, and help you get a more accurate age estimate.

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Years of jawbone data can provide insight to the health of an area deer herd. Image by Mark Olis

Why Aging Matters

To some hunters, age is the sole factor in determining whether to harvest a deer or not. A number of hardcore hunters in prime whitetail states refuse to target a deer unless they feel confident it has reached 5 ½ years of age. An older aged deer is typically harder to kill, produces a bigger rack, and poses a challenge many hunters find addicting.

But aging deer matters more than to just landowners attempting to grow mature bucks. Aging helps states and local biologists understand herd dynamics and health, which influences management decisions on regulations, seasons, and tag allotment. Sometimes agencies are at the mercy of state legislatures when it comes to management decisions, but sound scientific data such as deer aging can contribute to understanding the dynamics of a whitetail population and eventually provide information needed to make changes.

For example, using aging data over time in Chronic Wasting Disease hotspots can determine how a deer population is changing and reacting to the disease being present at a high prevalence rate. Over time, the absence of older bucks in an area previously populated with them could mean CWD is affecting that herd. Conversely, mature bucks testing negative likely indicates CWD or other diseases are not present at a high rate. Aging deer not only helps landowners understand their herd at the local level, but also clearly impacts how deer are managed in a broader sense.

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