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A common belief is that antlers are for fighting during the rut and for defense against predators. They are formidable and effective weapons which can be used in both situations. However, there is considerable potential to cause injury or death to an opponent of the same species. That is not in the best interest of the population. The problem of them having developed for use against predators is that females would have a greater need for them, than would the males, in order to protect their young. Also, the greatest need for defense against predators is during winter and most antlers are shed in early winter.
A rather novel concept for antlers was that of thermoregulation during summer. It was suggested that the blood flow through the growing antlers would help the animal dissipate excess heat. If that were the case, caribou would not be the only cervid with antlered females. Also, southern deer are exposed to higher temperatures than are northern deer but have smaller antlers. Experiments found that antler temperature did not change when the animals were subjected to both heat and cold stress.
Photo by Dave Johnson
Numerous studies have found that antlers have tremendous social significance. Perhaps the most spectacular demonstrations of this are from the work of Dr. Anthony Bubenik with antlered dummies. These involved head and neck mounts of several cervid species that are worn on a person’s chest. Each dummy can be fitted with replaceable antlers of various sizes in order to study an animal’s response to each size.
Reactions to these dummies vary from species to species. Moose were so overwhelmed by the dummy that they ignored human scent and accepted him as another moose. Caribou accepted the dummy, but looked behind him for the source of the human scent. Human scent made red deer and elk suspicious of the dummy but did not cause them to run off immediately.
An important feature of the dummies is being able to switch the size of antlers being displayed. When the dummy has small antlers and does not challenge a large antlered male, it is ignored. If the dummy has very large antlers, other lesser antlered bulls respect its personal space and may approach submissively. Red deer, elk, caribou and moose cows preferred the very large antlered dummy over live bulls. Caribou and moose cows would leave a courting bull for the dummy. In fact, two moose cows presented themselves to the dummy for breeding.
I should stress here that use of an antlered dummy should only be by one who is an expert on the behavior of the species involved. Not how it reacts to humans, for you are no longer considered a human. Every movement, or even your presence, is interpreted by the animal as that of a fellow member of that species. If you do something (intentionally, or not) it considers unwelcome or as a challenge, it will respond appropriately. The point of the use of dummies is to study and demonstrate animal behavior not to see how close one can come to being killed.
How antlers are displayed in social situations is very important and varies by species. This often depends on the size and shape of the species’ antlers and the habitat in which it lives. Species with short, sharp-tipped antlers (such as roe deer) make short, fast head movements which are easily noticed in dense cover. Red deer and elk have long antlers and often live in open to semi– open habitat and make long, slow head movements that can be seen from far away. Barren ground caribou have long antlers and tend to twist their body and lower their head nearly to the ground as there is no tall vegetation to obstruct view. Woodland caribou have somewhat shorter and larger diameter beams for easier travel through forested habitat and do not bow so low. Tundra moose also lower their head to show off their wide antlers (the palms of which face more forward than do the palms of woodland moose). Woodland moose palms are curved to slightly face each other for a narrower spread, thus easier travel in forested habitat and they also lower their head. Antlers of white-tailed deer curve forward and inward, with tines perpendicular to the beams, to lift branches and protect the face in dense cover; a nodding frontal display is typical and any clinging vegetation from thrashing of brush seems to improve their perceived status.
The classical antler display for each species allows individuals to better assess the social standing of potential opponents and thereby reduces serious fighting and the associated dangers. What many people think to be fighting is actually sparing. This activity has two values. The first is for learning how to use their antlers and is highly ritualized to avoid actual fights. The second is to learn how to assess their rank as compared to that of an opponent. They can see an opponent’s antlers, but not their own. They must relearn their rank each year until they are mature, and their antler shape and size remain rather consistent. Rutting males with no females may use a small tree as a sparring partner. This helps it to calm down so it will not remain in an agitated condition.
Actual fighting may happen when one intrudes on the personal space of another, fails to recognize warning behavior or signs, or they meet under poor conditions when they are unable to recognize each other’s rank. Often one will realize it is outmatched and will back off. If a fight ensues and the looser of the fight decides to leave, it must get out of the way of the victor very quickly. Now there is no longer any resistance to the victor’s push, he is unable to stop going forward and his antlers might then inflict serious and even fatal wounds.
One should not get the impression that behavior is always predictable. Sometimes a very small (and unnoticed) change from the usual situation can cause a different behavioral response. One thing is certain when dealing with wild animals, things may not go as expected. Dr. Bubenik once saw a mature bull go from sparring with an imaginary opponent to a fight with it. Apparently, the bull then decided it was the victor and chased off the imaginary opponent. Another day, the same bull again fought the imaginary opponent, but then decided it had lost the fight and fled with an expression of fear.
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