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Background Information, Habitat, and Feeding Behavior of the Giraffe

(Giraffa camelopardalis)

Giraffes eating from an Acacia tree.  Photograph provided by Dr. Case and used with her permission

Background

The giraffe is the tallest mammal in the world (15-19 ft. tall) and each individual giraffe can be recognized by its individual pattern of markings (Moss, 1975). There is some discrepency regarding the number of subspecies of giraffe, but currently, most researchers agree that there is only one species of giraffe, Giraffa camelopardalis, and eight subspecies. Interestingly, the scientific name comes from the old belief that the giraffe was a cross between and camel and a leopard (American Wildlife Foundation (AWF), 2002). The three most known subspecies of giraffe are the: Reticulated giraffe in northeastern Kenya, Rothschild's giraffe in western Kenya and eastern Uganda, Masai giraffe in southern Kenya. The five other subspecies of giraffe are the: Nubian, West African, Thornicroft's in Zambia, Angola, and the Cape giraffe in South Africa (Moss, 1975). The nearest relative of the giraffe is thought to be the okapi (Okapia johnstoni), which is rare and has been confined to the Congo Basin recently (Nature-Wildlife, 2002). The average lifespan of the giraffe is 25 years (AWF, 2002).

Habitat and Feeding Behavior

As briefly mentioned when describing the subspecies, giraffes inhabit the arid and dry African savannahs where the trees are and the bush country of the Sahara and are mainly found in East Africa (Moss, 1975). Giraffes are selective browsers and ruminants, spend much of their day (16-20 hours) browsing among the savannah for food, and eat anywhere from 15-75 pounds of food per day (AWF, 2002). They prefer to eat Acacia tree leaves and small twigs, but also eat the bark, fruit, and flowers of other trees and shrubs such as the Boscia and Cambretum trees (Moss, 1975). The diet of the giraffe changes with the wet and dry seasons, but giraffes usually find enough food because they move in loose herds through large homeranges in order to find adequate food. They do spend more time browsing for food during the dry season than the rainy season (Ciofolo, 2002). Giraffes eat deciduous trees in the rainy season and evergreen trees during the dry season (Le Pendu, 1999). Since the giraffe is a ruminant, it has a four-chambered stomach which serves to fully digest the initially barely chewed food (Ginnett, 1997). Rumination is done at all times of the day, although particuallarly in the evening and consumes about 3-5 hours of the day (Moss, 1975; Ginnett, 1997).

There is little competition for food because giraffes feed at a higher level than all other animals except the elephant, although they could obviously feed at lower levels. Also, male and female giraffes are different heights and thus eat at different vertical browse zones (Woolnough, 2001; Ginnett, 1997). Acacia trees are the mainstay of the giraffe diet despite their thorns because the tree is often green throughout the entire year and because the giraffe has a long and tough tongue and a prehensile upper lip (Moss, 1975).

No one has determined how much water a giraffe needs to survive, but it's not much. Some researchers concluded that giraffes don't need to drink water if their food has a high moisture content, which it does except during the height of the dry season (Moss, 1975). Foster also documented that when provided with water, giraffes will drink, but Mejia observed that giraffes did not seek out water when it was available (Moss, 1975). Besides the fact that giraffes get water from their food, another reason they don't drink much water might be because they are very vulnerable to predators while drinking. They have to spread their legs out so that their head can reach the water (Moss, 1975). Intrestingly, giraffes have a complex system of valves in their arteries and veins so that their blood doesn't flow to quickly and cause them to faint when they move their heads quickly up or down (Ciofolo, 2002).

Communication

It was thought for many years that giraffes did not make any vocal noises. This was found to not be the case (Moss, 1975). Calves make a mooing or mewing sound on occassion and adults sometimes moo, grunt, snort, or bleat (Moss, 1975). A giraffe might snort if it sees a predator, such as a lion or a man, but often other giraffes do not respond to this noise, so it is difficult to classify it as an alarm call (Moss, 1975).