Antlers - The Stuff of Dreams
For most white-tailed deer hunters, antlers are what make the world go 'round. Whether young or old, most of us have, at one time or another, dreamed of drawing on or lining up the crosshairs on a monster buck. The anticipation of this often stimulates us to separate with our hard-earned money (equipment, travel, lease fees, etc.), prods us to roll out of the sack at absurd hours and makes us eager to subsist on diets that probably take years off our lives. Since these head ornaments are so alluring to us, I thought we'd take a closer look at what they are and how they develop.
People use several terms when referring to antlers, the most common of which is "horns." However, antlers differ from horns quite dramatically. Cows, sheep, goats and bison have horns; deer (members of the Cervidae family) have antlers. Horns usually consist of a bony core covered by a keratinous sheath (similar to the material in a fingernail) that persists from year to year. Antlers, on the other hand, are composed of true bone and are grown and shed on an annual basis. In fact, antlers are the fastest-growing bone tissue known.
Antler growth for white-tails in the Noble Research Institute's service area usually begins during mid-March to April. The increase in day length in early spring stimulates hormone secretion in the pituitary gland, which in turn stimulates antler growth. While growing, antlers are covered in a specialized skin tissue called "velvet" (Figure 2). Velvet contains numerous blood vessels to aid in the transportation of minerals and nutrients during the antler growth phase. The growth phase continues throughout most of the summer.
Antler growth usually ceases in late August or September. Decreasing day length stimulates increased testosterone production, which triggers the hardening of the antlers and the velvet "drying up" and being shed or rubbed off. Hardened antlers usually are retained throughout the breeding season.
Antlers usually are cast or dropped some time during January to March as a result of decreased testosterone production. At this time, a separation layer forms at the pedicel (the antler growing point just below the burr) (Figure 3), and the antlers fall off.
This entire process repeats itself yearly.