AGING WHITETAIL DEER FROM THEIR JAWBONES
AGING WHITETAIL DEER FROM THEIR JAWBONES
The only way to truly tell the age of a deer, is to examine the teeth.
Within a few days of birth deer have seven teeth in the upper and lower jaw. These are Incisors, Canine and Premolars. Between 23 - 29 months these teeth have been replaced by permanent teeth.
The rear teeth, the molars, begin to erupt between 2 - 5 month with Molar 3 erupting between 18 - 24 months. Therefore deer can be aged quite accurately up to about 3 years of age by tooth eruption.
Diagrams reproduced from "Assessing age and condition of deer from jawbones" KW Fraser PJ Sweetapple by permission Manaaaki Whenua - Landcare Research NZ Ltd
The most accurate way to tell a deer's age is by removing a tooth, cutting a cross section of it, and counting the rings under a microscope, (much like aging a tree). Each winter, when a deer's blood-serum protein and phosphate levels are low, a layer of cementum is formed on the tooth.
Therefore the tooth has one layer for each subsequent winter the deer has lived through.
Over the last few years we have been collecting jawbones from Whitetail Deer to age them. The results clearly indicate that Whitetail on Stewart Island do not live to 20 years of age as some writers would have us believe. It also suggests that the trophy potential of bucks is declining at early as 9 - 10 years.
Stewart Island Whitetail Deer Research Group.
Deer ageing programme.
For some years we have been learning more about whitetail by aging animals that are shot. The table below records the ages of the first 1000 deer we have aged.
Ages established to July 2019
|
AGE in years |
-1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
|
Male # |
40 |
64 |
141 |
112 |
81 |
41 |
45 |
30 |
26 |
13 |
11 |
6 |
2 |
2 |
- |
1 |
1
|
|
Female # |
37 |
85 |
92 |
53 |
29 |
23 |
14 |
9 |
9 |
11 |
3 |
3 |
4 |
1 |
- |
- |
1
|
|
Unknown # |
2 |
3 |
1 |
|
|
Of these 1000 deer only 21 were over ten years of age.
Of the mature bucks:-
6 yr old: 14 point DS 141
6 yr old: 8 points DS 166 10 yr old: 9 points DS 144
6 yr old: 8 points DS 140 10 yr old: 4 points DS 66
7 yr old: 8 points DS 120 10 yr old: 5 inch spikes .
7 yr old: 8 points DS 167 11 yr old: 4 points
7 yr old: 11 points DS 150 11 yr old: 3 inch spikes
7 yr old: 8 points DS 150 11 yr old: 9 points DS 146
9 yr old: 4 points 13 yr old: 4 points DS 65
11 yr old: spikes 15 yr old: spikes
It would seem that bucks reach their peak potential at about 6 - 8 years of age and decline from 9 -10 years old.
Clean (preferably boiled) jaws can be sent to:
Stewart Island Whitetail Research Group, PO Box 1588 Invercargill 9840
Please ensure they are dry and wrapped in newspaper not plastic.
We need to know, sex, block, date and hunter’s name and contact details.
This is not a DoC project but one carried out by hunters wanting to learn a bit more about the whitetail deer we all enjoy hunting. Please assist by returning as many jaws as possible, even the very young ones.
We are keen to get as many jawbones as possible. Please send clean jawbones (one will do) to me. The best way is to give them a good boil. Boiling makes the teeth easier to get out.
It is essential we know which sex the deer was. Mark each jaw with your own code and gender. It is helpful to include any information about antler size with the bucks and any other observations you might like to add. We suspect many hunters don’t bother to send in jaws from fawns and yearlings as the age is obvious. We would like your young deer as well as jaw size may give an indication of animal condition.
Please supply block shot, sex, date and your name and address & email. We will advise the ages of all jaws supplied.