How To Age Whitetail Bucks on the Hoof

Aug 5, 2022 | Whitetail Hunting | 0 comments

Harvest Decisions

Deer hunting has undergone many changes over the last few decades. Hunting styles, strategies, and equipment have all seen dramatic improvements, increasing hunter success. Another change with a greater impact on the overall deer herd is hunters making harvest decisions based on the animal’s estimated age. The desire for hunters to harvest a mature buck has become more important than antler size in some circles.
Aging deer on the hoof (AOH) is difficult, period. Whitetail hunters are usually in two distinct camps when it comes to AOH; those claiming they can age any deer from 1.5 to 7.5 years old and those saying aging beyond 2.5 years old is virtually impossible. This article will likely spur some chatter from both camps.

Even Biologist Struggle with AOH

The Noble Research Institute, an independent non-profit agricultural research organization, recently completed a study which evaluated 108 deer biologist’s abilities to accurately age whitetail deer on the hoof. The age of each deer was known to the researchers. The deer biologists examined photos of deer ranging in age from 1.5 to 8.5 years old. The inaccuracy was astounding. Keep in mind these are deer biologists, people whose entire career is dedicated to the understanding and management of whitetail deer. This is not an effort to beat up on deer biologists around the country, but rather to show just how difficult AOH can be. Three-and-a-half and 4.5-year-old deer get a lot of attention where hunters are considering age and maturity. This study found 58% of the 3.5-year-old deer were incorrectly aged as being greater than 4 years old! Even young 1.5-year-old deer were often mistaken for being over 2 years old. The accuracy rate was only 62% for 1.5-year-old deer. As you can imagine the accuracy declined even further for older deer. The vast majority of deer over 5 were aged incorrectly.

Photo Credit: BaseMap user Erik Van Woerkom and his 2021 Nebraska whitetail buck.

Individualism

Part of the issues with AOH is the fact each buck is an unique individual. Most hunters realize several factors play a part in buck antler size. Obviously, age is very important, but things like nutrition, social stressors, and environmental stressors such as heat and cold have all been proven to affect antler development. If those factors result in differences in antler growth, then clearly those same factors are going to affect body condition. Better nutrition results in a stronger looking body. If some deer are traveling longer distances to fulfill their dietary requirements, while others are able to get everything they need in only a few acres of habitat, then clearly those deer traveling farther will have lower fat reserves. Deer suffering from weather or social stress may not fill out in the hips until a year or two later than expected. These are only a couple of examples of the countless reasons why deer might look different, even when they are the same age.

Genetics can also make a difference. Consider our own differences as humans. Think back to your high school locker room days. Everyone can probably remember their freshman year. All your classmates were about the same age. However, physical differences ran the spectrum of ultra skinny, tall, short, and built well enough to see starting time on the varsity football team. Some boys didn’t have a single whisker while a few could already grow a full beard. There is a wide variance in the timing of maturity of humans, and the same phenomenon occurs in other animals as well, including deer.

AOH Objective

Although more deer were aged incorrectly than accurately in this study, some data yields hope for hunters wanting to protect certain age classes of deer. If you define mature as 4.5 or older, then the need to age a deer to exactly 2.5 or 5.5 is irrelevant. As long as you can determine if the deer is younger or older than 4.5 years old you can effectively meet your objective. This research found none of the 1.5-year-old deer were accidently aged as 4.5 or older. Only 6% of the 2.5-year-olds were aged at 4.5 or older. The success slipped significantly at 3.5 years old where 38% were incorrectly aged as 4.5 or older. For the most part, assuming you can age a deer as well as the average deer biologist, targeting deer of 4.5 years and older of age protected almost all age 1.5 to 2.5 year-old deer. This strategy would also protect almost 2/3 of 3.5-year-old deer. For hunters who are holding out for 5.5 or 6.5-year-old deer to harvest, just realize there will likely be an occasional mistake and a younger deer might get harvested.

Aging Guidelines

Aging Whitetails on the Hoof Maturity Chart

Despite already pointing out how difficult deer aging can be, here are a few tips to help evaluate deer on the hoof – assuming the hunter is aging deer during the fall hunting season.

1.5-year-old deer are fairly easy to distinguish. These bucks typically have thin necks and minimal to no tarsal staining. Their legs appear too long for their body, and they have narrow chests and skinny waists. Basically they look like does with antlers.
2.5-year-old deer still have long legs. Most will have some swelling of the neck, but nothing compared to a truly mature deer. They will have some minor staining on their tarsal glands. Their chest is filling out, but they still have a narrow waist.
3.5-year-old deer are beginning to appear athletic. They have swollen necks, a muscular chest but still have not filled out in the hips. Think of this age as looking like a racehorse. They will have significant staining on their tarsal glands.
4.5-year-old deer have usually filled out in the hips and waist. Their waist is even with their chest. They have abnormally swollen necks and very dark stained tarsal glands.
5.5-year-old and older deer are getting lumped into one category. Specific features can be very difficult to distinguish beyond 4.5 years old and are not reliable and aging accuracy is difficult. Most will agree deer over 5 years old begin to have a pot belly look. They are getting their “dad bod” at this point. Their legs may even appear short for their body. However, some deer 5.5 years and older will still look like they are in peak shape. Therein lies the issues with accurately aging deer in this category.

Pair of Rutting Whitetail Deer Bucks in Colorado in Fall

Putting it All Together

Regardless of your objectives, nothing matters if you do not effectively execute a plan. Whether you consider a 4.5-year-old deer mature, or you believe deer should get a pass until 5.5 or 6.5 years of age, you still have to identify those animals to the best of your ability. Oftentimes, particularly when archery hunting, the hunter has only a few seconds from the first moment they see a buck until the shot opportunity occurs. If you are consistently hunting the same area and have the opportunity to run trail cameras, establishing a hit list, as well as a “no shoot” list, is probably the most effective way of protecting certain bucks. Trying to accurately age bucks with hundreds of pictures is difficult enough. Trying to decide whether a buck is 3.5 or 4.5 years old when he is trailing a doe, while you are preparing for the shot and focusing on drawing your bow or looking through your scope, all in the course of maybe 10 seconds, is nearly impossible. If you have a good assessment of the deer on the farm you are hunting, most bucks can be identified within seconds. There will always be the random new deer showing up, especially during the rut, you’ve never seen on camera, and you must make a quick assessment of his age. In those cases, do the best you can by assessing his physical characteristics. The ability of hunters to age deer on the hoof will always be debatable. During the season each hunter must decide what deer to harvest or pass and every harvested buck should be respected and revered, even if he turns out to be younger than you hoped.

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