Finding out a young deer's age by its teeth

When I find new deer skulls, or when I write about them here, I try to work out the age of them. Sometimes you can tell by the size, sometimes you can tell by whether the plates of the skull are fused, and sometimes the pedicles and antlers help. But the most useful way is to look at the teeth. The problem is that there is no proper guide which really helps, and the teeth of red and roe deer change at different types. There are guides like this one which don't go into enough detail and other guides like this which are okay but they are boring and written by scientists. So here is a guide I have written myself based on the red and roe deer skulls I have found.

About deer teeth

The dental formula for deer is:

Upper: 0:0-1:3:3

Lower: 3:1:3:3

That means on the top jaw there are no incisors, zero or one canines, three premolars and three molars on each side, and on the bottom jaw there are three incisors, one canine , three premolars and three molars on each side.

Scientists use the I1-3 (capital i) to refer to incisor teeth, C1 to refer to canines, PM1-3 for premolars and M1-3 for molars. Sometimes they use lower case letters for baby teeth (milk teeth or deciduous teeth) 

The canine on the lower jaw looks just like another incisor. The front eight teeth on deer and sheep are called incisoform, which means "looks like an incisor". Here are the teeth and their scientific names.

You can use incisors to tell the age of deer, but not often. I used the incisors to age this red spiker skull that I gave Mrs Powell because the adult I2 has just pushed out the baby I2:

The problem with incisors is they don't change much and they often fall out the jaws because they are loose.

Here is a young red deer hind skull showing where all the teeth are:

This red deer skull is unusual because it has a top canine which normally falls out. Muntjac and Chinese Water Deer can have much bigger canines like tusks like this:

How to tell the age of young roe and red deer using teeth

This is based on the skulls and jaws I have. They show the stages of deer goes through when its teeth are coming through, and what ages roe and red deer are at each stage. In all the pictures the front of the jaw is on the left, and the back of the jaw is on the right.

Before birth
Roe	Red	PM1	PM2	PM3	M1	M2	M3
before birth		emerging milk	emerging milk	emerging milk
Examples that I have like this: Wilma, the unborn red deer fawn.

Just before birth the three milk pre-molar teeth are coming through but not all the way up. The jaw is thin and fragile. You can see the hole already where the next tooth, the first molar, will come up through

At birth
Roe	Red	PM1	PM2	PM3	M1	M2	M3
0 months		milk	milk	milk	emerging adult
Examples I have: I only have lower jaws, not whole skulls like this.

When red and roe deer are born the three milk -re-molars are all the way through and the first molar is starting to come through (or erupt is what scientists say). There are no milk or baby molars, the teeth that come through are the adult ones.

An easy way to quickly see the age of a deer is to look at the lower pre-molar 3 (PM3) tooth. If it has three spikes, like this one, is is a baby or milk tooth and the deer is not older than 13 months if it is a roe, and not older than 30 months if it is a red. The adult pre-molar 3 has two spikes.

Because roe and red deer are born in late May/ early June, a deer with a jaw looks like this would have died in May/June of that year.

First molar (M1) comes through
Roe	Red	PM1	PM2	PM3	M1	M2	M3
1-2 mths	4-6 mths	milk	milk	milk	adult
Examples I written about: the young red deer stag

When deer are born they suckle milk from their mums. But soon they need their teeth to grind food for themselves. This is from a very young red deer, which was about 4-6months old. Roe deer get their teeth much quicker, so if a roe deer jaw looked this is would only be one or two months old.

Because roe and red deer are born in late May/ early June, a roe deer with a jaw looks like this would have died in July/August, and a red deer like this would have died in October-December.

Second molar (M2) comes through
Roe	Red	PM1	PM2	PM3	M1	M2	M3
9 mths	12 mths	milk	milk	milk	adult	adult
Examples I have written about: the young roe deer doe skull , the red deer spiker skull

The next stage is for the adult second molar to come through. This has two spikes, and it just comes through at the back, because there are no baby molars, just adult ones. This happens in roe deer when they are 9 months old, and in red deer when they are a year old.

Because roe and red deer are born in late May/ early June, a roe deer with a jaw looks like this would have died around March, and a red deer with teeth like this would have died around June.

Third molar comes through (M3)
Roe	Red	PM1	PM2	PM3	M1	M2	M3
11 mths	24 mths	milk	milk	milk	adult	adult	emerging

This looks almost the same as the picture above except in this one you can see the top of the third and final molar (M3) coming through. This would probably have just been coming through the gum. 

Because roe and red deer are born in late May/ early June, a roe deer with a jaw looks like this would have died around May, and a red deer with teeth like this would have died around May or June.

All adult teeth
Roe	Red	PM1	PM2	PM3	M1	M2	M3
13 mths or older	30 mths or older	adult	adult	adult	adult	adult	adult
Examples I have written about:  George (13 months old roe deer), the spiker red deer skull (30 months old with baby pre-molars about to be pushed out)

The next change comes really really quickly. The final molar comes up, and the baby pre-molars get replaced almost all at the same time. I know this happens all at the same time because I have a red deer spiker skull where you can actually lift out the baby pre-molar PM2 and PM3 teeth and see the adult teeth underneath. The adult PM1 comes up slightly before the adult PM2 and adult PM3.

When this happens, all the teeth are the adult teeth that the deer will have for the rest of its life. This happens by 13 months for roe deer, and by 30 months for red deer. This is also about the time that they have mostly grown to adult size.

How to tell the age of adult deer using teeth

It is difficult to tell the age of deer which have all their teeth. You have to make a guess on how the teeth are worn down. If they are worn down almost flat then it will be old, which is about nine years old for roe, and about 15 years for a red deer. It is easier to tell age from a bottom jaw because they wear out more.

If deer live on moors, their teeth wear down faster than deer living in forests or grasslands because heather (which you get on moors) is more difficult to eat than grass or leaves.

A gamekeeper gave me a tip of sawing through a tooth to count the rings but I have never tried it.

When deer get really old their teeth are at the gumline, it is difficult for them for them to grind food, and they can die from starvation. I have two deer skulls where this happened.

How to tell the age of sika, fallow and other deer

I only find roe and red deer skulls near where I live, but the Deer Commission for Scotland guide says red, sika and fallow deer are roughly the same. I'm not sure about muntjac or Chinese Water deer, which are the two other types you get in the UK.

I hope this helps and is not as boring as the scientific guides ! Leave a comment if you think I have made a mistake.

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