White-tailed Deer - Research Paper Example

? White-tailed Deer White-tailed Deer Introduction The white tailed deer or the Virginia deer is the most widely distributed hoofed animals in the United States. Its scientific name is Odocoileus virginianus. As Patent (2004) describes, thirty eight types of white tailed deer live in the United States, Canada, Mexico, Central America and South America. It has a brownish gray body with white hairs on the under side of the tail. During summer its color is reddish brown. Today the white tailed deer population is 18 million (pp. 5-11). They are found in deserts, swarms, farmlands, prairies. They mostly prefer living in open lands near the rivers and streams. As described in Zwaschka (1999), an adult male deer grows 41 inches tall and weigh about 160 pounds.(72 kgs) Female deer (doe) is smaller in size and they weigh 40-90 kgs on an average. The weight of white tailed deer varies from region to region. They live up to 10-20 years. It is herbivore and its feeding hours are in the early morning and late after noon. Its diet changes depending on the habitat and the season (pp. 4-10). It is a shy and cautious animal. They are good runners, leapers and swimmers. In alarming situations they flag their tails and run. The bucks alone have antlers that grow annually and fall off in the winter. Female deer gives birth to one to three young ones at a time, usually in the May or June. Their gestation period is 7 months. They are nocturnal and crepuscular animals. They are preyed up on by bobcats, coyotes and mountain lions. The scientific classification of white tailed deer; Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Artiodactyla Family: Cervidae Subfamily: Capreolinae Genus: Odocoileus Species: O. virginianus (Source: Squam Lakes Natural Science Center). Life Cycle The breeding season or rut extends from October to January though the majority occurs in October- November. Both bucks and does are seen active and they get out of their nocturnal habits during the breeding season. Patent (2004) describes the life cycle of white deer; the bucks rub their well developed antlers against big trees to mark their territories. These signs are called rubs. Bucks often fight with each other using antlers but fatal injuries are rare. During winter they shed off their antlers. But, antlers grow very fast, and those which grow will be stronger than the previous ones. (pp. 5-11). Antlers get their nourishment from a highly vascularized membrane called velvet which dries off which is rubbed against trees and shrubs. Fully grown antlers mark the breeding season for the bucks. Fawns are born after a 200 day gestation period. Two to three fawns are born in one litter. For the first few weeks the doe hides the fawns by themselves. The fawns have a spotted coat for the first 3-4 months but it is lost when the first winter comes. As described in National Geography website, when the mother goes in search of food the fawns lay flat on the ground quietly among the grass. They are scent free for few weeks to safe guard themselves from predators. Deer reproduces quickly and can over populate the area. To keep check on their numbers natural predators like bobcats and coyotes play a significant role (National Geography). Structure and function The organ system of the white tailed deer is same as that of any mammal. But its digestive system requires special mention. The front of the upper jaw bone does not have any teeth like other mammals. Teeth are replaced with a resilient pad which is in contact with the lower incisors. As Deal (2010) illustrates, they have 32 teeth. 8 incisors, 12 pre molars and 12 molars. They have a four chambered stomach. This ruminant stomach enables the deer to collect large quantity of food at a time, chew and digest it later. The deer pushes its food with its tongue to the back of the mouth where it is chewed. It is chewed just enough to swallow (p. 139). Then it is passed to the gullet of the stomach. The stomach is compartmentalized to four sections. They are the rumen, reticulum, omasum and abomasum. Food first reaches the rumen and it is stored there. It acts as a fermentation ground. The micro organisms present there acts up on the fiber and cellulose and converts in to forms which can be used by the deer’s digestive system. The rumen has spaghetti like fingers called papillae. These papillae and the lining of the rumen absorb acids from the food. This food is regurgitated to the mouth and this is called the cud. This is chewed and re- swallowed to the reticulum. The lining of the reticulum is like a honey comb. The food is clumped and it forms to the size of a soft ball. The reticulum filters out any foreign material in the food. After about sixteen hours food is passed to the third chamber omasum. Here intensive digestion and absorption takes place. Most of the water from the food is absorbed at this region. The abomasums has a smooth slippery lining with a dozen of elongated folds. Abomasum produces acid for further break down of food and nutrients are easily absorbed. The food then passes through the 67 feet long intestine and all the water is absorbed back leaving a mass of undigested particles which is excreted as feaces. Evolution The white tailed deer varies in its appearance from the diminutive Key deer of Florida to large northern forms. They are of different sub species and races. As per the findings of Ministry of environment, British Columbia (2000), after the melting of the Pleistocene glaciers, the white tailed deer spread northward in to the British Columbia from the north western states and north west from the Great plains in to Peace River region. This must have happened 15,000 to 10,000 years ago or more recently. This is strictly restricted to the Americas with no close relatives in any other continent. (pp. 11-13). Additional Interests White tailed deer exhibits elaborate social system. During the warm months, the basic social unit consists of related females, their fawns and yearlings. In autumn yearling males separate to up to 25 miles to establish permanent ranges with a different social unit. Each male competes with the others for access to females. Communication Signals The chemicals from the pedal, tarsal metatarsal and pre orbital glands help identifying the sex, age, identity and motivation of a deer. Deer deposits its glandular secretions by pressing the pre orbital glands on the twigs, by urinating on the hind limbs by rubbing the legs together. As Saunders (1998) illustrates, acts like lowering of head with ears in different position, presenting a lateral view of the body and standing on hind limbs and lashing out the front ones are all gestures of hostile encounters. Adults moan and bawl in varying contexts. Fawns give loud bleats to call their mothers and whine while nursing. References Deal, K. H. (2010). Wildlife and Natural Resource Management. US: Cengage Learning. Ministry of environment. British Columbia. (2000). White Tailed Deer in British Columbia. Ministry of environment. National Geographic. White tailed deer. Retrieved from http://animals.nationalgeographic.co.in/animals/mammals/white-tailed-deer Patent, D. H. (2004). White-tailed deer. Minneapolis: Lerner Publications. Saunders, D. A. (1998). White-tailed deer. EFS. Retrieved from http://www.esf.edu/aec/adks/mammals/wtd.htm Squam Lakes. Natural Science Center. Retrieved from http://www.nhnature.org/visit/animal_info_sheets/white_tailed_deer.php Zwaschka, M. (1999). The White-Tailed Deer. Capstone.   Read More