Aging Whitetail Deer At Various Stages

Aging a Yearling DeerYearling deer can be easily aged by examining the third tooth back on either side of the jaw. This tooth is called the third premolar. If this tooth has three cusps, the deer is 1 1/2 years old. If the third premolar has only two cusps, the deer is 1 year and seven months old or older.
75% of deer harvested in the U.S. are yearling deer.
Telling the Age of a Whitetail Buck
In December of 1998, the Field and Stream magazine had an article that I found interesting about a method for aging deer in the field. Here is my short version;
The twisting and turning of a deer's ears results in permanent creases in the hair and skin around the base of the ears. Deer 2 1/2 years or younger seldom have ear creases. But by 3 1/2 years the hair has thickened and taken on at least one crease. A two crease deer is a mature animal and is usually between 5 1/2 to 6 1/2 years old. If a deer has three creases at the base of the ears, it is likely about 7 1/2 years old give or take a year. If a deer has 4 ear creases, it is likely more than 8 years old. 
Also, as a deer ages, hair thickens in the ear slot. Finally, an older deer's ears tend to be more curled in and tired in appearance while a younger deer's ears will be flatter and more alert in appearance.
Telling the age of a deer with the ears method is most accurate on well conditioned animals.

Article By Tracker Outdoors
www.tracker-outdoors.com