I know hunting season is drawing to a close, but last week I wrote about deer vision, and one of my readers wrote and asked why I haven’t written about another sense that deer have … their nose. Here is a little bit about a complex subject.
Has this ever happened to you when hunting? On a cold November morning a hunter walks to his tree stand before daylight. He sits all day and sees nothing, but he knows there is a big buck in the area so the next morning he goes again. He notes the wind and enters the stand on a different path than the one he took the morning before. He sits all day and passes up shots at lesser deer waiting for the big buck. Just before dark he sees a dandy buck headed his way. Just out of bow range, the buck stops, puts his nose to the ground, turns and quickly walks away. The wind was perfect so the hunter is puzzled.
When he leaves his stand and walks to the spot where the buck turned away, he realizes that the buck intersected the trail he’d walked in the day before. Yes, a buck’s nose knows.
Hunters know that deer smell better than we can. Much better. Smell helps them find food, helps them communicate with other deer, helps them detect predators, etc. When researching this topic I found one neat study done in 2004 that got the researchers the Nobel Prize in Physiology on how humans detect doors. It turns out that we have a small patch of odor receptor cells inside our nose. Those cells make proteins that allow the detection of different odors. (This gets complex, but don’t go away). Genes determine the proteins that those cells make. So the ability for humans, and all mammals to smell, is tied to genes.
These researchers worked with mice (a mammal) and found that each protein in each odor receptor cell can allow mice to smell three different odors. Since mice have over 1,000 of these genes, they can potentially smell as many as 3,000 different odors. We don’t know how many genes deer have, but they definitely have way more than we do. One would guess that deer have at least 500 proteins and the genes to create them, and if each allows them to smell three odors, they could potentially smell 1,500 different odors.
This is important, but the next finding by these scientists is the kicker. These different odor receptor cells take in various odors, and send that information to the brain where patterns are formed. This means a deer can smell alfalfa one year and recall that olfactory memory the rest of its life. The deer forms a pattern based on everything that was going on when it smelled a certain odor. How does that benefit a deer?
Let’s say a deer walks into an alfalfa fied. Of course the deer sees the field, and it smells the alfalfa. That deer has been to the field many times, so there is a pattern already in the brain that says, “I see the field and I smell alfalfa, so it is time to chow down.” Odors create patterns and these patterns determine where a deer will eat. If a deer walks in a certain direction and smells an odor that is part of a pattern created a month before, then that tells him (or her) to continue in that direction and he/she will find food. It might be alfalfa, it might be acorns, or it might be turnips. The pattern was created and the deer reacts.
What if a dog chases a deer? The deer smelled the dog and then gets chased, and that is now a pattern in the deer’s brain. Next time he smells a dog, he will run away. If he is a young buck, then he might stand around a few seconds after seeing the second dog, and he may then get chased. Ah Ha!! The pattern is reinforced, so the third time he sees a dog, he is gone. Someone once told me that a buck isn’t all that smart, he just has great reaction time. True, and he is reacting to learned patterns in the brain tied to odors.
This whole pattern thing works the same when deer encounter hunters. That human odor could be cigarettes, perspiration, clothes, gasoline, after shave, you name it. If a deer encounters those odors while living in a park where there is no hunting, then it may not form a negative pattern. In fact, the deer may form a neutral pattern. Nothing bad happened when it smelled those odors, so the deer became accustomed to the presence of humans. In essence they became relative tame. Sounds like a lot of deer we have in Morgantown. Definitely deer we have in Greystone.
Maybe this explains why the best chance to take a big buck is often the first time you sit in a new stand. Lots more to discuss here, but I’m out of space. The bottom line is that you need to take all the steps possible to eliminate your door, because a buck’s nose knows and he doesn’t forget.
Dr. Dave Samuel is a retired wildlife professor from West Virginia University. His outdoor columns have appeared, and continue to appear, in Bowhunter magazine and the Whitetail Journal. If you have questions or comments on wildlife and conservation issues, email him at drdave4@comcast.net.
