Black tailed deer are a common game animal. The term “black tailed deer” defines one of nine subspecies of mule deer, known as Odocoileus hemionus. They have sometimes been treated as one species, but following further investigation, have been confirmed as subspecies. It is believed that the mule deer evolved from the black tails. Therefore, black tailed deer group, and the mule deer group are capable of hybridization.
They further separate into two distinct types, the first being the Sitka Black Tailed Deer (Odocoileus hemionus sitkensis), and the second being the Columbian Black Tailed Deer (Odocoileus hemionus columbianus). Both subspecies tend to be smaller and darker than white tailed deer (Odocoileus virginianus), and other types of mule deer.
Both subspecies inhabit Canada and the United States (US) in North America. More specifically, they occupy coastal woodlands from Northern California, through to the Pacific Northwest of the US. In Canada, they inhabit coastal British Columbia, up to Southeast Alaska (as far as Kodiak Islands!). As a species, they have not always lived as far West as they do now. In fact, they once used to occupy land as far East as Wyoming!
They are even referred to as the “Ghost Of The Pacific”! This is because they have a remarkable ability to move, unseen and unheard, through the wilderness. Hence why they are one of the least studied deer species in North America – they are very hard to pin down! They are secretive and stealthy, making them difficult to hunt, but a trophy if caught.
Their natural lifespan is relatively short, at just nine to ten years. However, this can be largely increased if bred and reared in captivity, even up to 20 years in some cases.
Mating and “Rutting”
In order to understand black tailed deer, it is important to study their mating behavior. This is also known as “rutting”, as a huge component of their mating formalities is ritualistic male on male competition. Other components include the chasing of the females by male deer! This can be observed first hand from roads and trails during mating season. Does seek to mate with bucks that have larger, stockier antlers.
Relatively, the mating or “rutting” season takes place for just a short period of time between November and early December. The males are known as bucks, and the females as does. During this time, the males will compete and fight for the affection of the doe in what is referred to as a rut. After a rut takes place, the bucks will seek a safe hiding spot to rest and recuperate. They often lose weight or nurse wounds, such as broken antlers, after the fight.
Following this is the gestation period, which lasts for roughly six to seven months. In late May and early June, the fawns begin to be born, even coming in twins or triplets on rare occasions! Their weight ranges between 6 and 9 pounds. Sadly, their mortality rate is extortionate! With 45-70% of fawns dying when young, mothers are understandably very protective. Humans especially are seen as a threat.
Bucks do not participate in raising their offspring, and in the summer join bachelor groups. In contrast, does form family groups, consisting of females and their young fawns. Each family group is led by the oldest mother, but young bucks must leave when approaching maturity at about 18 months old.
The individual pheromones and scent of a deer help the species to communicate. These are released from several specific glands located in the lower leg region of the animal.
The first, the metatarsal, is located on the outside of the lower leg. This produces an alarm scent, to heighten the senses of the deer and make it more alert. The tarsal, on the other hand, is located on the inside of the hock, and aids in mutual recognition between other black tailed deer. Finally, the interdigital gland, which is located between the toes, releases a scent that creates a trail when the deer travels across the habitat.
The markings and colorings of the deer vary throughout the year. So, while in summer they foster more reddish tones, in winter they tend to look more greyish brown.
They have relatively large ears, which move independently of each other! Their rather broad tails, that are either black or dark brown on the tip, are the defining feature to have given them their name. They also have a white undersurface that is exposed as a signal when they are frightened.
Sitka black tails are the slighter of the two subspecies, with bucks weighing approximately 120 pounds, and does just 80 pounds. Columbian black tails, however, have stockier bodies, albeit slightly slimmer legs. Bucks weigh far more, up to 200 pounds normally! Whilst does weigh up to 130 pounds.
Fun fact: They also have four stomachs! Being ruminants, this means that their food is barely chewed before it is swallowed. Following this, it is regurgitated, then rechewed and swallowed one last time. Three further stomachs then digest the contents before it even enters the intestine of the deer.
As is the case with most deer, bucks have antlers while does do not. Their antlers are dark brown in color, and branch identically on either side of their head.
Antler buttons begin to appear at just six to eight months old. Making it far easier to distinguish between male and female fawns. However, they do have a significant growth period, not becoming fully grown until the buck is four or five years of age.
Their antlers develop under a special type of skin, referred to as velvet. Which is removed upon full development of the antlers. This is, however, an annual cycle, as antlers are shed between December and March each year. From April up until August, a fresh pair of antlers begin to grow. They become bigger with each year of regrowth.
Sitka Black Tailed Deer (Odocoileus hemionus sitkensis)
What do the Sitka subspecies eat?
Sitka black tailed deer are herbivores, and their diet mostly consists of foliage from shrubs as well as herbs. Both are very important staples in the summer months in particular. Deers are browsers, and most of their food comes from scouting around the foliage.
In the winter months, however, their diet tends to consist of different components. For example forbs and bunchberry from evergreen trees. The forbs, however, can only be accessed when there is no snow. As otherwise they are covered and hard for the Sitka to spot or smell.
They also eat lichens all year round, which therefore make up a large component of their herbivore diet. These also come from evergreen trees. Grass, however, is rarely something that they feed on.
Where is the Sitka subspecies found?
Sitka black tails tend to be found inhabiting the rainforests of coastal locales. However, the height of their habitat is a major factor affecting their diet and distribution. Both subtypes prefer a cooler climate, with a mild temperature and ample rainfall.
For example, being in North America, the amount of snowfall is high throughout the winter months. This can easily obscure their food, and make scavenging in areas of higher elevation very difficult. For this reason, during the colder seasons, they need to inhabit forests that are less than 1,000 ft in terms of height.
Therefore, Sitka black tails can often be found in both Hemlock and Spruce forests during Winter. These forests, in particular, let in plenty of sunlight through the gaps in the canopy. This is beneficial for the feeding habits of Sitka, as it allows the adequate provision of sunlight for the growth of further shrubs and foliage that they feed on.
Columbian Black Tailed Deer (Odocoileus hemionus columbianus)
What do the Columbia subspecies eat?
Like the Sitka black tail, the Columbian black tail is also a herbivore. But although their diets are similar, they still differ in certain staples. Their feeding habits are also not exactly the same.
Shrubs and forbs form a large part of the diet of the Columbia subspecies, as it does with the Sitka black tail. They also enjoy lichens and mushrooms as staples of their diets, usually available all year round rather than seasonally. Furthermore, one of the plants that they browse is the Western poison oak, even though this tree gives off highly irritant content!
However, they tend to feed on grass in a way that the other subspecies does not. The grass consists of several types, in particular bluegrass, bromegrass, and orchardgrass. They also include berries in their diet on occasion, as well as cultivated crops such as corn or peas if they are available, much to the dismay of surrounding farmers!
Where is the Columbian subspecies found?
In contrast to the Sitka deer, habitats for the Columbian subspecies are far more diverse. They favor the outskirts of the forests, rather than the shelter of the canopy which lacks the underbrush. This allows them to wander freely between open grasslands, while still having access to the safety and hiding spots of the forest. Such a position also offers them shelter when storms or heavy rainfall passes through the area.
They also inhabit the mountainous areas of North America, unlike the Sitka black tails who favor the low altitude areas. Here they feed on the open grasslands at daybreak and nightfall when temperatures are moderate. If feeding during the night, they also seek out open areas. Although this does invite greater predation, due to the highly exposed environment.