If you’re interested in this you should start to save your jaws. I saved mine for decades and engrave some info on the inside bone to identify them, date, place, sex, and size.
These are yearlings, 1 ˝ years old. They have 6 teeth and are in various stages of losing their milk teeth, youngest to oldest top to bottom. The 3rd premolar, 3rd from the right, has 3 cusps as a milk tooth and 2 cusps as a mature tooth. The new premolars show a gap to the bone because they are not yet fully erupted. All molar crests show sharp peaks and the dentin (dark material below and inside the crests) is primarily showing only on the 1st molar. You can also see that the rear cusp on the final rear molar has just erupted. The 4th pic down has the 3 cusp milk tooth sitting on top of the new 2 cusp
These are 2 ˝ yrs. The 3 premolars are firmly in place. ALL 3 molars still have sharp crests and show some dentin. Rear cusp of rear molar has been above the gum line for some time.
These are 3 ˝ and beyond. 1st molar crest is not raised and sharp, a broader area of dentin is shown. In the top 3 (3 ˝ yr) the 2nd and 3rd molar crests are still obvious. The bottom jaw is “old”. The crests are gone, almost all enamel is gone, mostly just broad dentin. Teeth are worn right to the gum line. When you get much beyond 3 ˝ it becomes more of a guess.
This is a fawn, 6 mos. It only has 4 erupted teeth including the 3 cusp premolar. The 5th tooth is just beginning to show through the bone in the rear.
This is a 2 ˝ compared to a much older deer.