White-tailed Deer (Odocoileus virginianus) are a common sight throughout the Chautauqua-Allegheny region. These large mammals are often seen within the forests, fields and backyards that make up the area and all look relatively similar, having a brown and white body, big black eyes, black snouts and that characteristic white tail. This widespread ungulate often goes overlooked due to our familiarity with its presence and its rather ordinary look throughout most of the year. However, as autumn approaches, deer become much more interesting to some as males adorned with their large, bony antlers enter into the breeding season or the rut, and become a target for hunters, photographers and nature watchers.
This buck is displaying a rather unusual rack. The main beam of the antler above the buck’s left ear is significantly smaller than that of the antler above the buck’s right ear.
So what’s so interesting about antlers? As spring and summer progresses, the antlers of a male deer or buck will continuously grow. During this time, the antlers are covered in vascularized tissue referred to as velvet, which supplies the antlers with blood and minerals needed for proper growth. Towards the end of summer, blood flow slows and mineralization occurs, meaning the antlers become hardened bone, yep that’s right bone! As the blood flow stops, the velvet dies and dries. Bucks will remove the velvet from their antlers by rubbing them on trees or vegetation. Throughout the breeding season in autumn, bucks will use their antlers to intimidate or combat with other males in order to establish dominance and attract females to mate. After the breeding season is complete and the winter season is in full swing, cells will form around the base of the antlers, breaking down the minerals and causing them to eventually fall off. Come spring the process repeats.
Although growing antlers seems relatively simple, there is actually a lot more to it than one might think. Specifically, some studies have found that genetics, injuries, infections or environmental stressors such as drastic temperature changes, food availability and quality, pollutants, population density and parasites, amongst other factors, can create developmental instability in many species including white tailed deer. Bucks under such stresses may grow asymmetrical or non-typical antlers, with one antler being smaller than the other, or tines (points) growing both above or below the main beam of the antler, in clusters or in other abnormal configurations. According to some theories regarding sexual selection in deer, antler size and symmetry may indicate genetic quality as well as overall health of the buck to females, attracting them to bucks with larger and relatively symmetrical racks over males with smaller or asymmetrical racks. Antler size often has a direct relationship with age and the establishment of dominance also plays a role in sexual selection as well, but appearance seems to have some influence on female preferences too.
While it is difficult to determine why this particular buck’s antlers are asymmetrical, a number of elements may have influenced this past season’s growth. Genetics, injuries or environmental stressors such as this winter’s extreme temperatures or a large population are all factors that could have caused abnormal development of this individual’s antlers.
So, what’s the importance of humans seeing bucks with asymmetrical or non-typical antlers? Deer, just like many other local species, are indicators of habitat and population health. While it is difficult to confirm in any individual what exactly is causing the antlers to grow abnormally, taking notice of non-typical growth gets our attention and sparks our interest to investigate what’s going on in the environment. Human created stressors to the environment such as the introduction of pollutants or population stressors such as overpopulation, for example, can be actively managed in order to restore habitat health and balance the population numbers with the limited resources within a habitat. Furthermore, deer are only one of several species that reside in deciduous forests, farmers fields and our own backyards, so management of the deer populations also helps many other species thrive as well.
So the next time you see a buck, whether it be while you are out leaf peeping, hunting or hiking, take a closer look at the antlers and see how symmetrical they are, it could be indicative of the deer’s health and its habitat!
Elyse Henshaw
Conservation Technician
