Sunday, December 7, 2014

Giraffe camelopardalis

 Giraffe camelopardalis is in the order Artiodactyla which are even toed ungulates (hoofed animals). Their weight is supported equally by the third and fourth toes like cattle, camels, and hippopotamus. It is the world's tallest animal and the largest ruminant. Giraffe camelopardalis are broken into 9 subspecies listed in the image below. 16) Among these nine subspecies there has been extensive genetic testing providing analysis that show some of these subspecies may be their own separate species. Giraffe camelopardalis are in the class Mammalia which is a group of endothermic amniotes with the synapomorphies of hair, three middle ear bones , mammary glands, and a neocortex. 8)


Range and Habitat
Giraffe camelopardalis are located in arid and dry-savanna zones of sub-Saharan Africa. The growth of human population has constricted the range of these animals. Small populations are spread out on a wide range of Africa. Different sub-species can be found in Chad to the north all the way to South Africa. They also reach from Niger in the west to Somalia in the east. These animals usual inhabit savannas, grasslands, and open woodlands. A giraffe's diet restricts it to where it can live. They feed on the leaves of trees like the Acacia, Commiphora, and Terminalia. Open woodlands with these types of trees are the primary habitats for giraffes. Giraffes aren't found in dense forested areas because their height would limit their ability to maneuver through the trees. During the wet season, Giraffe camelopardalis are found in a broader area due to the abundance of food resources. Once the dry season approaches Giraffes are forced to live closer to one another in order to feed off the remaining resources.  16)

Physical Description 
 Giraffe camelopardalis are the tallest land mammals in the world. They can reach heights of anywhere between 20 and 15 feet and can weigh anywhere between 4,250 to 1,200 pounds. Males are often taller and heavier than females. Like all mammals, the giraffe has 7 cervical vertebrae and when elongated, can be about 10 inches long. The vertebrae are connected by ball and socket joints. The vertebrae also have large extensions for muscle and ligament attachment. Giraffes have a nuchal ligament that runs from the top of the head all the way to the base of the tail and acts like a rubber band. These modifications give the giraffe excellent balance, flexibility and durability of the neck and head. 9)  Males and females both have horn like structures on top of their heads though they are not true horns. They are permanent bony structures that are covered with hair and skin. The horns can grow up to 5.3 inches. Horns are different between the sexes. Males' horns are larger and the ends don't contain hair, while females and the young are smaller and are tufted with hair. Another sexual dimorphism of the giraffe is the skull. Mature male heads are often bumpy and rigid looking due to extra ossification over the front of the skull, around the eyes, and on the rostrum. Females may have added knobs similar to males but they are not as extensive as males. 11) One unique characteristic of giraffes are their prehensile tongues that measure up to 20 inches. They use them for grasping foliage and cleaning their nose. Giraffes pelage differs among the nine sub-species. Each sub-species has a unique pattern and color to their spots. The spots can range from dark brown to a lighter tan. The patterns are very unique and can be seen in the image below. 10)

Giraffe camelopardalis heads are about 2 meters away from their heart. One of the giraffes unique physiology is its ability to supply blood to the head. A giraffe's heart has to deal with the hydrostatic pressure applied by all the blood in the neck and also has to be strong enough the overcome gravity forcing the blood back to the heart. Science has shown that giraffes maintain a very high blood pressure, almost twice that of other animals. Many would think giraffe hearts are very large but this is not the case. Giraffe hearts are actually smaller compared to their body size. The difference is that the walls of the heart are much thicker than other mammals. Their heart has evolved to be able to pump blood in a smaller radius with large muscular walls. It's able to maintain these high pressures without having severe vascular lesions or heart and kidney failure. Science have studied these animals to figure out how they deal with hypertension. They found that small vessels forming at the ends of the carotids have elastic walls that allow them to withstand the strong pressures. When a giraffe drinks, it lowers its head. These small vessels are able to control the amount of blood reaching the head. This prevents the brain from being flooded with blood. A giraffe's diet has also been found to help prevent hypertension. 15) A giraffe's blood is very similar to humans. It has similar viscosity and protein content. Recent studies have shown that Acacia leaves, which is a major food source for giraffes, contain compounds that prevent hypertension. Scientists think the gum found in the leaves protect the organs and prevent them from failure. Scientist don't fully understand the process but future studies hope to understand these detailed processes. 5)

 Giraffe camelopardalis are non-territorial social animals. They travel in herds known as towers that are not organized in any specific order. These groups can number in different sexes and ages. Though female giraffes often will be in a herd with a couple of young males. There is no true structure to the groups. Sexual mature males will use their horns and long necks to strike and fight other males for dominance and mating rights. 16) Reproduction among giraffes is mostly polygamous. Sexual mature males will most often mate with young adult females. The males will taste the females urine to determine if she is fertile or not. Once a male has picked a female to mate with, he will court her and keep other males away until copulation is finished. Pregnant females gestation last anywhere between 400 and 460 days. Females give birth standing up and once the calve hits the ground it takes only a few hours for it to stand and begin running. Mothers giraffes often form nurseries, where one mother will leave her calf with another so she can feed and drink elsewhere. The bond mothers and calves have with each other varies. Some females will nurture her young for several months while others take care of them until she gives birth again. 14)  When giraffes aren't focusing on mating they are most likely grazing for food. Giraffes spend most of the daylight hours feeding and ruminating. Feeding is at its highest during the first and last hour of daylight. They mainly feed off the leaves of Acacia, Commiphora, and Terminalia trees. They have also known to feed on shrubs, grass , and fruit. Studies have shown that when the leaves run short, giraffes will begin feeding on grass. This is not typically preferred because this makes the giraffe vulnerable to predator attack since it must bend over to reach the grasses. Giraffes consume up to 75 pounds of foliage a day. At night they rest standing up while ruminating the food consumed during that day. 13)

Conservation Status
 In the past 10 years the giraffe population has decreased by almost half from 140,000 to 80,000. Even though they are still numerous, there is concern that several sub-species may go extinct in the near future. The International Union for Conservation of Nature has placed two sub-species on the endangered list which are the Western African Giraffe and the Rothschild giraffe. 6) Much of their habitat has been destroyed and is being invaded by humans. Other problems such as poaching and hunting has also lead to the decrease in population. Hunters target giraffes for their meat, tail hairs, and hides. Much of these items are sold and bought on the black market. There are several organizations that have been set up to protect giraffe population. 7) One of these organizations is the WCS (Wildlife Conservation Society) which has monitored giraffe populations to ensure the prevention of habitat loss and illegal hunting. They have helped governments in these areas to form laws and regulations to protect these animals. There are also programs set up to educate local people on the giraffe population. With these efforts the WCS hopes to prevent the population from decreasing. 3)

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