Giraffes Research Paper

Irene Anderson

Mammalogy Lab

Emily Evans

20 April 2015

Giraffes, Uncovered

Giraffes are the tallest mammals on Earth and that is why I chose to write a paper on them. I want to learn more about them and how they have evolved and survived throughout evolutionary history. Giraffes are in the order Artiodactyla, family Giraffidae, genus Giraffa and species Giraffa camelopardalis. They are native to Africa, mainly found in southern parts, below the Sahara. Giraffes inhabit dry, arid land like savannas, grasslands, or open woodlands. Giraffes are herbivores and more specifically browsers, meaning that they eat foliage off of trees, like leaves or fruits. They are also ruminants and have a four-chambered stomach. The diet of a giraffe consists of

leaves, flowers, seedpods, and fruits and their main food source is the leaves of the Acacia tree. They seek out areas where there is rich growth of this tree. Giraffes use their prehensile tongue to pull leaves off of trees and for self-cleaning behaviors. Their upper lip is also prehensile and used in feeding. Giraffes have a very wide home range. It varies from 5 to 654 km2, depending on food and water availability.
Giraffes are the world’s largest mammals.

Male giraffes stand at about 18 ft. and females can reach up to 15 ft. At birth calves are about 6 ft. tall. All giraffes have a spotted coat, which helps with camouflage in the scrub forests. The coat is like a fingerprint and stays the same for the giraffe’s entire life. The internal systems of a giraffe are amazing. The blood pressure of a giraffe is twice that of a human and the heart is about the size of a basketball. Giraffes have legs that are long and sturdy. The blood vessels of the legs are under immense pressure because of the weight of fluid pressing down on them. To solve this problem, the skin around the legs is tight and thick to prevent blood pooling. Additionally, the front legs are longer than the back ones. Giraffes have long necks that can be up to 2 m long. The necks contain 7 elongated vertebrae and there are varying theories about how the neck evolved. One theory, the “competing browsers hypothesis” hypothesized by Charles Darwin, suggests, “competitive pressure from smaller browsers encouraged the elongation of the neck, as it enabled giraffes to reach food that competitors could not” (Wikipedia, 2015). The other theory is the “sexual selection hypothesis” that suggests that the long necks were selected for sexually. Both theories seem plausible, but the sexual selection hypothesis does not account for why females have long

necks.
Living in the African savanna, there are a lot of possible predators for the giraffe. Lions are the main predators, but leopards and hyenas also prey on giraffes. However, giraffes are able to defend themselves against these predators. They can run up to 30mph and deliver deadly kicks with their legs.
Giraffes have a polygynous mating system. This means that males mate with more than one female per mating season. Conception occurs in the rainy season, and birth occurs in the dry season, from May to August. The average gestation period for a female giraffe is about 457 days, and females breed every 20 to 30 months. Mother giraffes give birth standing up or walking and the calf will drop about 6 ft. to the ground. After about fifteen minutes, newborn calves are walking and suckling on their mother’s teat. The average weaning age for a calf is 12 months. After about 1-3 years, a giraffe becomes independent from its mother. At 3 to 4 years of age, a female giraffe will become sexually mature. Males become sexually mature at 4 to 5 years of age. The average lifespan of a giraffe in the wild is 10 to 15 years and 20 to 25 years in captivity.
Giraffes in general are not endangered and on the Lease Concern list made by the International Union for Conservation of Nature (IUNC). There are some subspecies of giraffes that are on the endangered species list like, G.c. peralta and G.c. rothschildi. One reason for the endangerment is poaching. Humans hunt giraffes for their skin, meat, and tail. Habitat degradation is also a factor. Deforestation because of the creation of grazing room and the need for firewood has caused giraffe decline in eastern Africa, where they are very scarce.
The research topic I choose is giraffe behavior. There are many studies involving giraffe behavior and being the largest mammal in the world, I am interested to finding out more information about how they behave. Studying animal behavior is important because is the link between the environment and evolution. Evolution is a continuous response to past and present environmental conditions. When an animal evolves to with the changing environment, behavior also evolves. There are several different techniques used when recording animal behavior, all of which require observation of the animal. Ad libitum sampling is when the observer watches the animals and takes notes on everything that seems relevant and is visible. This method does not have constraints on which animal to watch. Focal animal sampling involves the observer watching and taking notes on one individual animal within a specific time window. Scan sampling involves the observer taking notes on many individuals at regular time intervals. Behavior sampling requires the observer to note whenever a specific behavior happens and what individual performs it.
An advantage to doing observational research is that it encompasses a wide range sampling methods to choose from.

Depending on the resources available to the researcher, they can choose a variety ways to conduct the research. It also gives the researcher a first person view of how the animal is behaving, without having to watch it in a video or read another persons account. Observational research also goes along well with other forms of research, giving the researcher another perspective to look at. There are disadvantages in observational research as well. Observational research is very time consuming and also requires copious amounts of resources. The research will always be limited by the amount of resources that are required to complete it. Observer bias and observer effect can also be disadvantages. If the researcher reports information that they wanted to see or thought they saw, that would render the research an unreliable source. Also, if the researcher’s presence affects the animal’s behavior, then the observation would not be accurate, and again, the research would be

unreliable.
The significance of all of this information is to show that observational research is a good way to study the behavior of giraffes. While there are advantages and disadvantages, those occur with every researching technique. The behavioral study of giraffes will help the population as a whole understand giraffes better. With the ongoing conservation efforts, it will allow the conservationist to better educate themselves and the human population about the importance of giraffes and help them build adequate conservation areas in order to save them. It will help zoos and already existing conservation centers do the same. Studying the animal behavior of giraffes will most likely lead to the discovery of other symbiotic or asymbiotic relationships with other organisms, which could lead to further discoveries about the savanna habitat in as a whole.