ArrayNovember 24, 2013 at 11:36 am
Collecting Deer Data - Part 2
In the first post about deer bio-data collection, I talked about where wildlife biologists go to collect information and measurements from harvested deer. In this part, I’ll tell you what measurements and samples we collect and why. The first thing the biologist takes note of is the seal number. This is the seven digit number on the registration tag which is affixed to the animal at the tagging station. This number provides an easy way to keep all of the samples and meat connected to the specific deer organized. The seal number allows us to determine where the deer was tagged and also goes on the envelope of any tooth or sample that is taken so we know who to contact with information that may be derived from those samples. Next the biologist will note the date and the town and county in which the deer was harvested. The gender is also noted. If the deer is female and still has teats attached, the biologist will check for signs of lactation. If the deer has antlers the number of points is counted: a point must be at least 1 inch long to be counted. If the deer is a yearling (one and a half years old) or could be a yearling, the diameter of the antler beam (the bottom piece of the antler from which the tines branch from) is also measured on one of the two antlers. Antler beam diameter on yearlings is directly influenced by the amount of food available to that individual deer. Small antler beam diameters may mean that there are too many deer in that area, and thus each individual deer does not have enough food for optimal antler growth. The weight of the deer is noted only if that weight was obtained using a certified scale and if the deer at the time of weighing was fully dressed (with the heart, lungs, and liver all removed). The age of the deer is the next measurement required. Sometimes a deer’s age can be determined by its teeth. Often a fawn still has [caption id="attachment_228" align="alignright" width="240"] This fawn jaw has four molars on each side. Each molar has multiple cusps. Notice the third molar has three cusps because this is a young deer.[/caption] its baby teeth. The incisors (front teeth) appear small and needle-like. It also has fewer than six molars (back teeth) on each side of the bottom jaw. This is because the last molars have not erupted from the gums yet. A yearling can sometimes be aged by a quick glance at the teeth as well. At one and a half years of age, the yearling will replace the third molar from the front on the bottom jaw with an adult tooth. The baby tooth in this position has three visible ridges (cusps), and is referred to as tricuspid. The adult tooth coming in has only two cusps (so the tooth is called bicuspid). Yearlings are often at various stages of replacing this tooth when they are harvested. Some still have the tricuspid tooth with no signs of replacing it yet. Some have the tricuspid tooth, but it is detached from the gums and looks like a cap on top of the bicuspid tooth coming in. Some have completely lost the tricuspid tooth, but the bicuspid one they now have appears very clean, white, and new compared to the surrounding teeth. Regardless of which of these stages the deer is at, it is a yearling. If the third molar back on the bottom jaw is bicuspid and appears to have as much wear as the surrounding teeth, the deer is likely an adult (2 and a half years of age or older). If this is the case, the biologist will pull one of the front bottom teeth for aging. A [caption id="attachment_229" align="alignright" width="240"] This jaw is from a yearling. You can clearly see the adult bicuspid third molar erupting. The tricuspid cap on the third molar has fallen off, but is clearly visible on the second molar, with the adult second molar erupting underneath the baby tooth cap.[/caption] miniscule sliver will be cut from the tooth and age can be determined by viewing the sliver under a microscope and counting the rings of compression, much like one would age a tree. All of this information is vital to comprehending the health of Maine’s deer herd. When a biologist calls you or knocks on your door after you’ve registered a deer, don’t worry. We are excited that you’ve harvested a deer and we are hoping to capitalize of the opportunity to learn as much about the local deer herd as we can. We appreciate the cooperation and information we receive from all of the meat processors, tagging stations, and hunters statewide. Thank you. [caption id="attachment_230" align="alignnone" width="300"] Can you tell which of these two deer is an adult and which is a yearling? If you guessed the yearling was on the right, you are correct. The third molar on this yearling is still the baby tricuspid tooth.[/caption]
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