Why is age important? Whitetail bucks as a group tend to produce their very best antlers once they mature in body. With most bucks their skeletal system growth is completed when they are about 4 years of age. Up until the time all a buck's bones are completely developed, body development is always going to take precedence over antler development. That's why older bucks, 4 year olds and older produce the biggest antlers.
Back during the 1960's Texas wildlife biologists, namely Jack Ward Thomas, Rod Marburger, Charlie Ramsey and others developed a technique to age hunter-harvested deer by looking at tooth eruption and wear on the deer's lower jaw, looking at their premolar and molars. Deer have six "jaw teeth" on each side of their lower jaw, three premolars and three molars. Looking at incisors, those in the front really can't tell you anything in terms of a deer's age.
Yearling bucks, those that are 1 1/2 (always a half year in the fall due to the fact they were born more or less in the spring), generally show wear on their first two premolars. If you didn't look any farther you might suspect the buck is really old. But if you look a bit farther back you'll notice the third premolar has three cusps or crests (somewhat like peaks). Up until the time a deer is about 19 months of age, the third premolar will be a tooth that has three crests. At about 20 months of age the three premolars are replaced and the third premolar is replaced with a tooth that has two crests. Whenever you look at a deer's teeth to age it, especially if it is a smaller bodied and smaller antlered buck, is to look at the third premolar tooth. If it has three cusps, the deer is a yearling (1 1/2 years old).
After that it gets a bit more difficult to age a deer but we can still generally age deer within a year or so. Diet and quality of the diet can have some bearing on how a deer's teeth wear. What follows is basic description of how deer age according to tooth wear. Essentially a deer's teeth wear from the center of the jaw forward and backward. Also of note is that it is important to look at both sides of the lower jaw, each called a "ramus". Some deer are right-jawed and some left-jawed, meaning they spend more time chewing on one side or the other.
1. At 2 1/2 years of age all the teeth are present and none really show any appreciable wear. All the cusps are relatively pointed and sharp.
2. At 3 1/2 years of age the crest of the teeth are starting to show some wear and becoming a bit blunt, and the last cusp on the last tooth looks a bit concave.
3. In typical 4 1/2 year olds the crests of the teeth are almost worn away, and the last cusp on the last tooth is worn so badly that its surface sloped outward and downward. The dentine, the softer inner core of the tooth (much darker in color as compared to the enamel), is as wide as the enamel on the fourth, fifth and sixth tooth.
4. By the time the deer is 5 1/2 years old the crests of the teeth are nearly worn completely smooth and the dentine is considerably wider than the enamel.
5. At 6 1/2 the crest of the teeth are practically gone and most of the teeth appear to be flat. There is also considerable wear on the premolars.
6. By the time the deer is 7 1/2 years old all the teeth are worn flat and show tremendous wear. After that it gets a bit difficult to accurately age deer.
Learning how to field-age deer and then by looking at their teeth adds another dimension to deer hunting, and that knowledge will make you a better deer hunter and manager.
Bonus Video: Age This Whitetail