When mid-November rolls around, white tailed deer start thinking about breeding and the antlers on the bucks are all about breeding. When mid-November rolls around white tailed deer hunters start thinking about antlers as well, though for different reasons. When it comes to deer antlers, the more points the better — both for amorous deer as well as for individuals who love hunting deer.
First and foremost, the hard, bone-like growths which develop on the heads of male deer once they are a year or more old are antlers, not horns. The major difference between horns and antlers is that horns are a permanent part of an animal and in many species, both males and females grow horns.
Antlers on the other hand, on deer and most other antlered species, are grown only by males. Antlers grow during a part of the year, serve their purpose and then fall off. A new, probably larger set of antlers are then grown the following year, those are shed and the antler cycle continues.
The reason some species of animals, such as bison, water buffalo, pronghorns and others, grow permanent horns is because the purpose of their horns is mainly defensive and warding off predators is equally important for both sexes. For the most part, horns play only a minor role during the breeding process.
Though species like deer, moose and elk which grow antlers can and do use their antlers to ward off cougars or wolves, that’s not their major purpose. If antlerless female deer and cow elk manage to survive in a predator filled environment without any antlers, why would the larger, stronger males need to have them? A deer’s antlers aren’t needed until the mating season.
Deer don’t mate for life, they don’t even pair-up, “two by two” during the breeding season. Among the male deer in an area, the breeding season becomes a battleground and the winner of the battles get to breed with the most does; most of the losers won’t get to breed with any.
Buck battles resulting in cuts or other wounds to either of the combantents are uncommon and battles to the death are even more rare. The fights are usually simple shoving matches. The bucks push against each other’s antlers and the one with the greatest strength wins. Deer with the largest antlers are usually larger and stronger overall than bucks with smaller antlers. Both sexes of deer realize this.
A six month old male deer certainly realizes this because he doesn’t even have antlers, just nubs or buttons where his antlers will sprout as he gets older. No sense “bucking heads” with any older deer which does have antlers.
When he does grow his first set of antlers they will be small — decidedly smaller than deer which are two years old, three or older. He might engage in a shoving match with another buck his own age, but he’ll shy away from the older bucks. Younger bucks can spot the headgear on other bucks and gauge their size before deciding to run or fight.
Even if they decide to fight, the winner may still be a loser in the long run. While the bucks are battling the does are observing and choosing. The final decision of which buck gets to father a doe’s fawns is made by the female deer; and when given a choice, females select the buck with the larger antlers because they instinctively know larger antlers suggests increased fitness.
Sexual selection for antlers by females is what caused antlers to evolve into such large and costly ornaments. After shedding old antlers after the breeding season, new antlers begin to grow almost immediately. Deer antlers are the fastest growing tissue in the world and can grow more than one inch per day. Growing antlers use so much calcium and phosphorus so quickly bucks go through a temporary form of osteoporosis, stealing these minerals from their bones during antler development.
Males will start growing antlers when they are close to their first birthday. In the Midwest where most deer are well fed with nutritious food, this first set of antlers will usually have four or six antler points, occasionally eight. The following year’s set will likely develop with two or more additional points so a young six-pointer may be an eight-pointer the following year, but that trend won’t necessarily continue as the buck ages.
Most deer reach their peak antler development between 4 and 7 years of age and most will top out at having between eight and 12 total points. The exact antler size and potential is controlled by three things: age, nutrition, and genetics.
When food supply is reduced in quantity or quality, the result is poor antler growth. This can happen if deer herds get too large. High concentrations of deer can destroy habitat and cause loss of essential plant species. Without their preferred browse plants, deer nutrition suffers, and antlers decrease in size as a result. This is one of many reasons regulated hunting and habitat management are so important.