They are the fastest growing bone material known to man, and over a course of days from late March through early August, a mature buck can grow in excess of inches of bone on his head. Many believe that having great summer growing conditions is the key to optimum antler growth.
Though extremely important, there is far more to the antler growing equation than having a great growing season. For a buck to truly reach his potential he must be healthy and have great food sources year round. If either of these factors is lacking he will not reach his potential. As a result, it is important that good nutrition be available to bucks every month of the year. Seasonal changes and rainfall will affect the levels of protein in forage and, as stated above, supplemental feeding is often used to support antler growth.
What we do know is that, just like other animals, genetics are a two-part equation, and both the mother and the father play equally important roles. Genetics will determine the shape and size of the antler, and studies have shown that big antlers are hereditary more on this later. Before a buck can be called a monster, a hawg, a toad, or booner, it has to survive a few seasons. Like the best things in life, antlers get better with time. A whitetail buck will reach generally reach his prime in four to six years , and for elk, it is more like eight to twelve.
Age is one of the easiest factors humans can manipulate to see bigger antlers. Regulations like point restrictions and deer camp customs like passing up smaller bucks can be helpful. Male cervids have two soft spots on their skulls called pedicles. In the spring or early summer, two nubs form at the pedicles and are covered in a sensitive type of skin called velvet.
The velvet is packed with blood vessels that rapidly bring blood, oxygen, and nutrients that the antlers need for growth. The antlers grow from the tip, starting as cartilage and then calcify into hard bone as they go. During the velvet stage, cervids try to avoid contacting their antlers with just about everything.
Injuries to velvet during antler growth can cause changes. Once the antlers are fully grown, the velvet is cut off from the blood supply, and it dries up and dies before getting rubbed off by the animal.
Throughout the season, the connections between the pedicles and the antlers weaken, and usually during the winter, well after mating, the antlers fall off.
In a matter of weeks, the cycle starts all over again. Depending on the photoperiod, or amount of sunlight during the day that a male cervid is exposed to, they will either be growing or shedding their antlers. Generally, the more sunlight there is, the more the antlers will grow. In the chondroprogenitor region these young cells begin to differentiate into chondrocytes and to form the columnar structure characteristic of cartilage and bone.
The enlarged and columnar chondrocytes then begin the process of mineralization. Once mineralized, chondroclasts resorb the cartilage, and bone is laid down on the remaining "scaffold" by osteoblasts. For more details on this process see the review by Price et al. There are two types of bone within an antler, spongy bone and compact cortical bone.
Spongy bone makes up the inner portion and is less dense, softer, and weaker. Spongy bone is highly vascularized during growth, which allows the transport of nutrients and growth regulating hormones.
Compact bone forms the outer shell of the antler, and its greater density and stiffness provide strength for fighting. Spongy bone makes up about half the diameter of an average antler McDonald et al. Antler shape or form, known as conformation, is highly variable and depends on age, genetics, and nutrition.
Points or tines are classified as typical points generally symmetric and arising from the top of the main beam and abnormal or non-typical points arising from other than the top of the main beam or asymmetrical with the other side. Abnormalities include kicker points projecting laterally from a tine or beam, drop tines projecting downward from a main beam, extra main beams, palmation of the main beam or between tines, and clustered tines.
Some deer antlers exhibit annual variation in conformation, and a deer's last antler set may be quite abnormal. Throughout the winter, the antler begins to weaken in preparation for casting in the spring. Bucks occasionally drop their antlers in late winter rather than early spring. Antlers aren't the only type of headgear that mammals sport! Some animals, such as goats, bison, pronghorn and sheep, grow horns from their heads.
Members of the deer family, also known as the Cervidae family, grow antlers. In the vast majority of cases, antlers only grow on male animals, with the exception of the caribou. Unlike antlers, horns do grow on both genders, with the females growing smaller horns than males.
While antlers fall off and regrow on a yearly basis, horns do not shed and continue to grow throughout the animal's life. The only exception to this rule is the pronghorn, which sheds the sheath around its horn every year. Antlers also consist primarily of bone and do not have blood vessels after their velvet dries up and the antlers harden. Conversely, horns consist of a keratin sheath with a bony core, with blood vessels running between the two on a permanent basis.
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