In West Africa, Giraffe formerly ranged from Senegal to Lake Chad, but the only viable surviving population within this entire area is a small population in south-western Niger with a range of about 15,000 km² (Boulet et al. 2004). This represents the only surviving wild population of G. c. peralta; a small population observed in the Ansongo-Menaka Partial Faunal Reserve in Mali, on the border of Niger, is presumed to be extinct.
Giraffe are still present in northern Cameroon, southern Chad, Central African Republic and in Garamba National Park in north-eastern Democratic Republic of Congo (East 1999); there is limited information on their occurrence in Sudan, west of the Nile (where they were not recorded at all during the course of recent surveys), but they do still occur in the south-east (in Boma National Park) (Fay et al. 2007). In East and north-east Africa, Giraffe still occur in relatively large numbers in northern Kenya, mainly outside protected areas, in south-western and southern Ethiopia, Somalia, and in small numbers in a few protected areas in Uganda; they are now extinct in Eritrea. Giraffe remain relatively widely distributed through southern
There is an isolated population of Giraffe (Thornicroft’s Giraffe G. c. thornicrofti) in the Luangwa Valley (Zambia).
In southern Africa, having been reintroduced to many parts of the range from which they were eliminated, Giraffes are currently common both inside and outside a number of protected areas in Namibia, Botswana, Zimbabwe and South Africa. In Angola, the Giraffe is now assumed to be extinct. A few animals are reported to still survive in Sioma Ngwezi National Park in south-western Zambia, while in Mozambique, a few individuals still occur in the area adjacent to Kruger National Park. Giraffe have been introduced to
Giraffa camelopardalis is native to Africa, mainly found south of the Sahara to eastern Transvaal, Natal, and northern Botswana. Giraffes have disappeared from most of western Africa, except a residual population in Niger. They have been reintroduced in South Africa to game reserves.
Biogeographic Regions: ethiopian (Native )
- 2003. Grzimek's Animal Life Encyclopedia. Pp. 399-408 in M Hutchins, D Kleiman, V Geist, M McDade, eds. Okapis and giraffes, Vol. 15: IV, 2 Edition. Farmington Hills, MI: Gale Group.
Giraffa camelopardalis is the world’s tallest mammal. Male giraffes (bulls) stand a total of 5.7 m from the ground to their horns: 3.3 m at the shoulders with a long neck of 2.4 m. Female giraffes (cows) are 0.7 to 1 m shorter than bulls. Bulls weigh up to 1,930 kg, while cows can weigh up to 1,180 kg. At birth, giraffe calves are 2 m tall from the ground to the shoulders. Newborn giraffes weigh 50 to 55 kg.
Both male and female giraffes have a spotted coat. The pattern of the coat varies and is an aide for camouflage with the different habitats. The nine giraffe subspecies have various skin patterns. The patches on a giraffe coat can be small, medium, or large in size. Giraffe coats are sharp-edged or fuzzy-edged; small, medium, or large; or yellow to black in color. The skin pattern for an individual giraffe is constant throughout the giraffe’s life. With the changing of season and health, the coat color may be altered.
Giraffa camelopardalis have long, sturdy legs, with their front legs longer than their back legs. Giraffe necks contain 7 elongated vertebrae. Giraffes have a steeply sloping back from the shoulders to the rump. Their tails are thin and long, measuring about 76 to 101 cm in length. A black tuft at the end of the tail whisks away flies and other flying insects. Giraffe horns, called ossicones, are bone protuberances covered with skin and fur. Female giraffe horns are thin and tufted; male giraffe horns are thick but the hair is smoothed by sparring. A medium-sized horn is common in both male and females; while males can grow a second pair behind the first pair of horns. The eyes are very large and their 45 cm long black tongue grasps prickly food from the very tops of trees.
Range mass: 1180 to 1930 kg.
Range length: 4.7 to 5.7 m.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: male larger; ornamentation
- Burnie, D., D. Wilson. 2001. Smithsonian Institution Animal: The Definitive Visual Guide to the World's Wildlife. New York: DK Publishing, Inc..
Habitat and Ecology
Giraffes inhabits arid, dry land. They seek out areas enriched with Acacia growth. Giraffes are found in savannas, grasslands, or open woodlands. Because they only occasionally drink, giraffes can be found away from a water source. Male giraffes can venture into denser wooded areas in search of more foliage.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: savanna or grassland ; scrub forest
- 1999. Walker's Mammals of the World. Pp. 1084-1089 in R Nowak, ed. Okapi and Giraffe, Vol. 2, 6 Edition. Baltimore, Maryland: The Johns Hopkins University Press.
Giraffes feed on leaves, flowers, seed pods, and fruits. In areas where the savanna floor is salty or full of minerals, they eat soil as well. Giraffes are ruminants and have a four-chambered stomach. Chewing cud while traveling helps to maximize their feeding opportunities.
Giraffa camelopardalis have long tongues, narrow muzzles, and flexible upper lips to help obtain leaves from the tall trees they use for browsing. Giraffes use many tree species for browse, including: Acacia senegal, Mimosa pudica, Combretum micranthum, and Prunus armeniaca. Their main food is the leaves from Acacia trees. Giraffes browse by taking the branches in their mouths and pulling away the head to tear away the leaves. Acacia trees have thorns but giraffe molars crush the thorns. Up to 66 kg of food for one day can be consumed by an adult, male giraffe. However, in poor-quality areas, a giraffe can survive on 7 kg of food per day.
Male giraffes typically feed with their head and neck completely outstretched to the shoots. Their fodder is from the underside of the high canopy. Female giraffes feed at body and knee height, feeding from the crown of lower trees or shrubs. Female giraffes are more selective when feeding. They choose foliage with highest nutritional value.
Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; fruit; flowers
Primary Diet: herbivore (Folivore )
Giraffes are host to troublesome ticks. Oxpecker birds (Buphagus africanus) rests on the backs and necks of giraffes, removing the ticks from the giraffe skin. There is a mutually beneficial relationship between giraffes and oxpecker birds.
- oxpecker bird (Buphagus africanus)
- ticks (Acari)
Lions (Panthera leo) are the main predators of giraffes; while leopards (Panthera pardus) and (hyenas Hyaena hyaena) have also been known to prey on giraffes. Adult giraffes are well able to defend themselves. They remain vigilant and are capable of running quickly and delivering deadly blows with their front hooves. Crocodiles may also prey on giraffes when they come to waterholes to drink. Most predators of giraffes target young, sick, or elderly giraffes. The blotchy color of giraffe skin also helps to camouflage them while foraging in scrub forests.
Anti-predator Adaptations: cryptic
Life History and Behavior
Video of male Giraffes fighting with their necks can be viewed at ARKive.
Communication and Perception
Giraffa camelopardalis are rarely heard and are usually considered silent mammals. Giraffes communicate with one another by infrasonic sound. They do, at times, vocalize to one another by grunts or whistle-like cries. Some other communication sounds for giraffes are moaning, snoring, hissing, and flutelike sounds. When alarmed, a giraffe grunts or snorts to warn neighboring giraffes of the danger. Mother giraffes can whistle to their young calves. Also, cows search for their lost young by making bellowing calls. The calves return their mother’s calls by bleating or mewing. While courting an estrous cow, male giraffes may cough raucously.
Giraffe vision relies mainly on their height. Their height allows giraffes a continual visual contact while at great distances from their herd. The acute eyesight of giraffes can spot predators at a distance so they can prepare to defend themselves by kicking. Individuals within a herd may scatter widely across the grassland in search of good food or drink, and only cluster together at good food trees or if threatened.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: duets
Perception Channels: visual ; acoustic
Giraffa camelopardalis have a life expectancy between 20 to 27 years in zoos. Giraffes live for 10 to 15 years in the wild.
Status: wild: 25 (high) years.
Status: captivity: 27 (high) years.
Status: wild: 10 to 15 years.
Status: captivity: 20 to 25 years.
Status: captivity: 25 years.
- 2005. "Animal Fact Sheet" (On-line). Reticulated Giraffe. Accessed November 19, 2005 at http://www.zoo.org/educate/fact_sheets/savana/giraffe.htm.
Lifespan, longevity, and ageing
Giraffes are polgynous. Bulls carefully guard an estrous female from other male giraffes. Courtship starts when a bull approaches a cow to perform a urine test, smelling the urine with a pronounced lip curl, a behavior referred to as flehmen. The bull will then proceed to rub his head near the rump of the female and rest it on her back. Male giraffes lick the tail of the female and lift his foreleg. If receptive, the female giraffe will circle the male, hold her tail out, and take on a mating position, after which copulation occurs.
Mating System: polygynous
For Giraffa camelopardalis, conception occurs in the rainy season, with birth occurring in the dry months. Most giraffe births take place from May to August. Female giraffes breed every 20 to 30 months. The gestation period is about 457 days. Mother giraffes give birth standing up or walking. The giraffe calf drops 2 m to the ground. Most often a single calf is born; twins are uncommon but do occur. Newborn calves get to their feet and begin suckling fifteen minutes after birth. The weaning period for female calves is 12 to 16 months; the weaning period for males is 12 to 14 months. The independence period varies between bulls and cows. Cows tend to stay within the herd. However, bulls tend to become solitary until they find or obtain their own herd and become the dominant male. Female giraffes reach sexual maturity at 3 to 4 years of age but do not breed for at least another year. At age 4 to 5 years, male giraffe become sexually mature; however, it is not until seven years of age when they start to breed.
Breeding interval: Giraffes can give birth every 20 to 30 months
Breeding season: Breeding occurs between May and August.
Range number of offspring: 1 (low) .
Range gestation period: 400 to 468 days.
Average gestation period: 457 days.
Range weaning age: 12 to 16 months.
Average weaning age: 12 months.
Range time to independence: 1 to 3 years.
Range age at sexual or reproductive maturity (female): 3 to 4 years.
Range age at sexual or reproductive maturity (male): 4 to 5 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous
Average birth mass: 58500 g.
Average number of offspring: 1.
A giraffe calf hides throughout much of the day and night of its first week, remaining on the ground. Mother giraffes stay nearby, within 25 m, guarding their young and feeding. At night females return to their young to nurse them.
After three to four weeks, mother giraffes steer their young calves into crèche groups. The crèche group allows mother giraffes to wander further away from the young calf to feed or drink. The mother giraffes take turns watching over all the youngsters in the crèche group. Now the mother giraffe can drift as far as 200 m from her calf. Mothers still return before nightfall to suckle and protect their calf.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female)
- 1997. Encyclopedia of Mammals. Pp. 809-833 in A Brown, et. al., eds. Browsing Giants, Vol. 6. Tarrytown, New York: Marshall Cavendish Corp..
- 2003. Grzimek's Animal Life Encyclopedia. Pp. 399-408 in M Hutchins, D Kleiman, V Geist, M McDade, eds. Okapis and giraffes, Vol. 15: IV, 2 Edition. Farmington Hills, MI: Gale Group.
Evolution and Systematics
The tongues and mouths of giraffes and other ungulates are protected when eating thorny plants because they are leathery.
"Yet giraffe and camels and goats have developed tongues that are so long, mobile and dexterous that they can select and grasp any particular shoot that they want, and the linings to their mouths seem to be so leathery that they can close around the thorns without damage of any kind." (Attenborough 1995:61)
Learn more about this functional adaptation.
- Attenborough, D. 1995. The Private Life of Plants: A Natural History of Plant Behavior. London: BBC Books. 320 p.
Tight skin of giraffe legs assists blood circulation by creating extravascular pressure.
"Its [giraffe's] heart is two-and-a-half times as big as zoologists would expect for an animal of its size. And the skin around its legs is unusually tight. Pedley [Tim Pedley of the University of Cambridge] says that high blood pressure would encourage blood to pool in a giraffe's legs. The tight skin acts like a support stocking, forcing blood back up into the body." (Thomas 1997:24)
Learn more about this functional adaptation.
- Thomas, Jim. 1997. A heart for heights. New Scientist. (2100): 24.
The skin and hair of giraffes may repel ticks, mosquitoes and bacteria via secreted chemical compounds, particularly indole, skatole, and p-cresol.
"…two alkaloids, indole and 3-methylindole (skatole), are primarily responsible for the scent of the giraffe…Indole occurs naturally in the floral scent of jasmine, orange blossom and other flowers (Poucher, 1974). Indole and 3-methylindole have an intense faecal odour at high concentrations that becomes pleasant in very dilute solutions — both are used in perfumery (Poucher, 1974)…Many of these compounds may function as antimicrobial agents…The growth of two ubiquitous species of skin bacteria is inhibited by some of the giraffe-derived compounds…Another possible function of these compounds may be to repel ectoparasitic arthropods. Both indole and skatole were judged by Rudolfs (1922, 1930) to repel wildcaught mosquitoes (Aedes spp.) from the US, but quantitative results are needed to affirm this. A tick found in areas inhabited by giraffes, Rhipicephalus appendiculatus, is repelled by p-cresol, one of the giraffe skin compounds…" (Wood and Weldon 2003:915-916)
Learn more about this functional adaptation.
- Wood, W. F.; Weldon, P. J. 2002. The scent of the reticulated giraffe (Giraffa camelopardalis reticulata). Biochemical Systematics and Ecology. 30(10): 913-917.
Molecular Biology and Genetics
Statistics of barcoding coverage: Giraffa camelopardalis
Public Records: 3
Specimens with Barcodes: 4
Species With Barcodes: 1
Barcode data: Giraffa camelopardalis
There are 5 barcode sequences available from BOLD and GenBank. Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species. See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
IUCN Red List Assessment
Red List Category
Red List Criteria
- 1996Lower Risk/conservation dependent
Giraffa camelopardalis populations seem to be stable throughout parts of their range and are threatened in other areas. Giraffes are hunted and poached for their skin, meat, and tail. Habitat destruction also impacts giraffe populations. Giraffe populations remain common in east and southern Africa but have drastically fallen in west Africa. In Niger, conservation of giraffes has been made a priority. In other places where large mammals have disappeared, giraffes have survived. Their survival could be because their height diminishes competition with domestic mammals.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
The population in Niger estimated to number 79 animals in 1999 (Ciofolo et al. 2000), has since increased to more than 200 animals in 2007 ( J Suraud pers. obs.).
In 1998 there was an estimated population of more than 500 Rothschild’s (and Nubian) giraffe, with the populations from Sudan unknown (East 1999). There were an estimated 2,500 individuals in Murchison Falls National Park in the 1960s, declining sharply to 350 in 1982–1983 and 250 in 1995–1996. The current population in Murchison Falls National Park is estimated to be of 240 individuals and stable. The reintroduced population in
In Niger, conservation projects have facilitated the Niger Giraffe’s population recovery in an area outside any formal protected park or reserve. However, poaching and habitat loss and degradation as a result of increased aridity, and expansion of human activities remain threats (Ciofolo and Pendu in press). This small population survives only in the wild, since the Giraffes held in captivity in the Vincennes Zoo, France, which were long considered to represent peralta, in fact belong to the subspecies antiquorum (Hassanin et al. 2007).
Rothschild's Giraffe is one of the most imperilled Giraffe subspecies remaining. Exact numbers of giraffes in
Relevance to Humans and Ecosystems
Economic Importance for Humans: Negative
There are no known adverse effects of giraffes on humans.
Economic Importance for Humans: Positive
In many zoos and wildlife parks, giraffes serve as an attraction. Giraffes have been killed for their meat and hide. The thick skin has been made into buckets, reins, whips, straps for harnesses, and sometime for musical instruments.
Positive Impacts: food ; body parts are source of valuable material
The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest living terrestrial animal and the largest ruminant. Its species name refers to its camel-like appearance and the patches of color on its fur. Its chief distinguishing characteristics are its extremely long neck and legs, its horn-like ossicones and its distinctive coat patterns. It stands 5–6 m (16–20 ft) tall and has an average weight of 1,600 kg (3,500 lb) for males and 830 kg (1,830 lb) for females. It is classified under the family Giraffidae, along with its closest extant relative, the okapi. The nine subspecies are distinguished by their coat patterns.
The giraffe's scattered range extends from Chad in the north to South Africa in the south, and from Niger in the west to Somalia in the east. Giraffes usually inhabit savannas, grasslands, and open woodlands. Their primary food source is acacia leaves, which they browse at heights most other herbivores cannot reach. Giraffes are preyed on by lions, and calves are also targeted by leopards, spotted hyenas and wild dogs. Adult giraffes do not have strong social bonds, though they do gather in loose aggregations if they happen to be moving in the same general direction. Males establish social hierarchies through "necking", which are combat bouts where the neck is used as a weapon. Dominant males gain mating access to females, which bear the sole responsibility for raising the young.
The giraffe has intrigued various cultures, both ancient and modern, for its peculiar appearance, and has often been featured in paintings, books and cartoons. It is classified by the International Union for Conservation of Nature as Least Concern, but has been extirpated from many parts of its former range, and some subspecies are classified as Endangered. Nevertheless, giraffes are still found in numerous national parks and game reserves.
- 1 Etymology
- 2 Taxonomy and evolution
- 3 Appearance and anatomy
- 4 Behavior and ecology
- 5 Relationship with humans
- 6 References
- 7 External links
The name "giraffe" has its earliest known origins in the Arabic word zarafa (زرافة), perhaps from some African language. The name is translated as "fast-walker". There were several Middle English spellings such as jarraf, ziraph, and gerfauntz. The word possibly was derived from the animal's Somali name geri. The Italian form giraffa arose in the 1590s. The modern English form developed around 1600 from the French girafe. The species name camelopardalis is from Latin.
Kameelperd is also the name for the species in Afrikaans. Other African names for the giraffe include ekorii (Ateso), kanyiet (Elgon), nduida (Gikuyu), tiga (Kalenjin and Luo), ndwiya (Kamba), nudululu (Kihehe), ntegha (Kinyaturu), ondere (Lugbara), etiika (Luhya), kuri (Ma'di), oloodo-kirragata or olchangito-oodo (Maasai), lenywa (Meru), hori (Pare), lment (Samburu) and twiga (Swahili and others) in the east;:313 and tutwa (Lozi), nthutlwa (Shangaan), indlulamitsi (Siswati), thutlwa (Sotho), thuda (Venda) and ndlulamithi (Zulu) in the south.
Taxonomy and evolution
The giraffe belongs to suborder Ruminantia, and many Ruminantia have been described from the Mid-Eocene in Central Asia, Southeast Asia, and North America. The ecological conditions during this period may have facilitated their rapid dispersal. The giraffe is one of only two living species of the family Giraffidae, the other being the okapi. The family was once much more extensive, with over 10 fossil genera described. Their closest known relatives are the extinct climacocerids. They, together with the family Antilocapridae (whose only extant species is the pronghorn) belong to the superfamily Giraffoidea. These animals evolved from the extinct family Palaeomerycidae 8 million years ago (mya) in south-central Europe during the Miocene epoch.
While some ancient giraffids like Sivatherium had massive bodies, others like Giraffokeryx, Palaeotragus (possible ancestor of the okapi), Samotherium, and Bohlinia were more elongated. Bohlinia entered China and northern India in response to climate change. From here, the genus Giraffa evolved and, around 7 mya, entered Africa. Further climate changes caused the extinction of the Asian giraffes, while the African ones survived and radiated into several new species. G. camelopardalis arose around 1 mya in eastern Africa during the Pleistocene. Some biologists suggest that the modern giraffe descended from G. jumae; others find G. gracilis a more likely candidate. The main driver for the evolution of the giraffes is believed to have been the change from extensive forests to more open habitats, which began 8 mya. Some researchers have hypothesized this new habitat with a different diet, including Acacia, may have exposed giraffe ancestors to toxins that caused higher mutation rates and a higher rate of evolution.
The giraffe was one of the many species first described by Carl Linnaeus in 1758. He gave it the binomial name Cervus camelopardalis. Morten Thrane Brünnich classified the genus Giraffa in 1772. In the early 19th century, Jean-Baptiste Lamarck believed the giraffe's long neck was an "acquired characteristic", developed as generations of ancestral giraffes strove to reach the leaves of tall trees. This theory was eventually rejected, and scientists now believe the giraffe's neck arose through Darwinian natural selection—that ancestral giraffes with long necks thereby had a competitive advantage that better enabled them to reproduce and pass on their genes.
Up to nine subspecies of giraffe are recognized (with population estimates as of 2010[update]):
- The Nubian giraffe, G. c. camelopardalis, the nominate subspecies, is found in eastern South Sudan and south-western Ethiopia. Fewer than 250 are thought to remain in the wild, although this number is uncertain. It is rare in captivity, although a group is kept at Al Ain Zoo in the United Arab Emirates. In 2003, this group numbered 14.
- The reticulated giraffe, G. c. reticulata, also known as the Somali giraffe, is native to north-eastern Kenya, southern Ethiopia, and Somalia. An estimated population of no more than 5,000 remain in the wild, and based on International Species Information System records, more than 450 are kept in zoos.
- The Angolan giraffe, G. c. angolensis, or the Namibian giraffe, is found in northern Namibia, south-western Zambia, Botswana, and western Zimbabwe. A 2009 genetic study on this subspecies suggests the northern Namib Desert and Etosha National Park populations form a separate subspecies. It is estimated that no more than 20,000 remain in the wild; and approximately 20 are kept in zoos.
- The Kordofan giraffe, G. c. antiquorum, has a distribution which includes southern Chad, the Central African Republic, northern Cameroon, and north-eastern DR Congo. Populations in Cameroon were formerly included in G. c. peralta, but this was incorrect. No more than 3,000 are believed to remain in the wild. Considerable confusion has existed over the status of this subspecies and G. c. peralta in zoos. In 2007, all alleged G. c. peralta in European zoos were shown to be, in fact, G. c. antiquorum. With this correction, about 65 are kept in zoos.
- The Masai giraffe, G. c. tippelskirchi, also known as the Kilimanjaro giraffe, can be found in central and southern Kenya and in Tanzania. No more than 40,000 are thought to remain in the wild, and about 100 are kept in zoos.
- The Rothschild giraffe, G. c. rothschildi named for Walter Rothschild, is also called the Baringo or Ugandan giraffe. Its range includes parts of Uganda and Kenya. Its presence in South Sudan is uncertain. Fewer than 700 are believed to remain in the wild, and more than 450 are kept in zoos.
- The South African giraffe, G. c. giraffa, is found in northern South Africa, southern Botswana, southern Zimbabwe, and south-western Mozambique. Less than 12,000 are estimated to remain in the wild, and around 45 are kept in zoos.
- The Rhodesian giraffe, G. c. thornicrofti, also called the Thornicroft giraffe after Harry Scott Thornicroft, is restricted to the Luangwa Valley in eastern Zambia. No more than 1,500 remain in the wild, with none kept in zoos.
- The West African giraffe, G. c. peralta, also known as the Niger or Nigerian giraffe, is endemic to south-western Niger. Fewer than 220 individuals remain in the wild. Giraffes in Cameroon were formerly believed to belong to this subspecies, but are actually G. c. antiquorum. This error resulted in some confusion over its status in zoos, but in 2007, it was established that all "G. c. peralta" kept in European zoos actually are G. c. antiquorum.
Giraffe subspecies are distinguished by their coat patterns. The reticulated and Masai giraffes represent two extremes of giraffe patch shapes. The former has neatly shaped patches, while the latter has jagged ones. The width of the lines separating the patches also differ. The West African giraffe has thick lines, while the Nubian and reticulated giraffes have thin ones.:321–22 The former also has a lighter pelage than other subspecies.:322
A 2007 study on the genetics of six subspecies—the West African, Rothschild, reticulated, Masai, Angolan, and South African giraffe—suggests they may, in fact, be separate species. The study deduced from genetic drift in nuclear and mitochondrial DNA (mtDNA) that giraffes from these populations are reproductively isolated and rarely interbreed, though no natural obstacles block their mutual access. This includes adjacent populations of Rothschild, reticulated, and Masai giraffes. The Masai giraffe may also consist of a few species separated by the Rift Valley. Reticulated and Masai giraffes have the highest mtDNA diversity, which is consistent with the fact that giraffes originated in eastern Africa. Populations further north evolved from the former, while those to the south evolved from the latter. Giraffes appear to select mates of the same coat type, which are imprinted on them as calves. The implications of these findings for the conservation of giraffes were summarised by David Brown, lead author of the study, who told BBC News: "Lumping all giraffes into one species obscures the reality that some kinds of giraffe are on the brink. Some of these populations number only a few hundred individuals and need immediate protection."
The West African giraffe is more closely related to the Rothchild and reticulated giraffes than to the Kordofan giraffe. Its ancestor may have migrated from eastern to northern Africa and then to its current range with the development of the Sahara desert. At its largest, Lake Chad may have acted as a barrier between West African and Kordofan giraffes during the Holocene.
Appearance and anatomy
|Wikimedia Commons has media related to Giraffa camelopardalis anatomy.|
Fully grown giraffes stand 5–6 m (16–20 ft) tall, with males taller than females. The average weight is 1,192 kg (2,628 lb) for an adult male and 828 kg (1,825 lb) for an adult female. Despite its long neck and legs, the giraffe's body is relatively short.:66 Located at both sides of the head, the giraffe's large, bulging eyes give it good all-round vision from its great height.:25 Giraffes see in color:26 and their senses of hearing and smell are also sharp. The animal can close its muscular nostrils to protect against sandstorms and ants.:27 The giraffe's prehensile tongue is about 50 cm (20 in) long. It is purplish-black in color, perhaps to protect against sunburn, and is useful for grasping foliage, as well as for grooming and cleaning the animal's nose.:27 The upper lip of the giraffe is also prehensile and useful when foraging. The lips, tongue and inside of the mouth are covered in papillae to protect against thorns.
The coat has dark blotches or patches (which can be orange, chestnut, brown or nearly black in color) separated by light hair (usually white or cream in color). Male giraffes become darker as they age. The coat pattern serves as camouflage, allowing it to blend in the light and shade patterns of savanna woodlands. The skin underneath the dark areas may serve as windows for thermoregulation, being sites for complex blood vessel systems and large sweat glands. Each individual giraffe has a unique coat pattern. The skin of a giraffe is mostly gray. It is also thick and allows it to run through thorn bush without being punctured.:34 The fur may serve as a chemical defence, as its parasite repellents give the animal a characteristic scent. At least 11 main aromatic chemicals are in the fur, although indole and 3-methylindole are responsible for most of the smell. Because the males have a stronger odor than the females, the odor may also have sexual function. Along the animal's neck is a mane made of short, erect hairs. The one-meter (3.3-ft) tail ends in a long, dark tuft of hair and is used as a defense against insects.:36
Skull and ossicones
Both sexes have prominent horn-like structures called ossicones, which are formed from ossified cartilage, covered in skin and fused to the skull at the parietal bones. Being vascularized, the ossicones may have a role in thermoregulation, and are also used in combat between males. Appearance is a reliable guide to the sex or age of a giraffe: the ossicones of females and young are thin and display tufts of hair on top, whereas those of adult males end in knobs and tend to be bald on top. Also, a median lump, which is more prominent in males, emerges at the front of the skull. Males develop calcium deposits that form bumps on their skulls as they age. A giraffe's skull is lightened by multiple sinuses.:70 However, as males age, their skulls become heavier and more club-like, helping them become more dominant in combat. The upper jaw has a grooved palate and lacks front teeth.:26 The giraffe's molars have a rough surface.:27
Legs, locomotion and posture
The front and back legs of a giraffe are about the same length. The radius and ulna of the front legs are articulated by the carpus, which, while structurally equivalent to the human wrist, functions as a knee. The foot of the giraffe reaches a diameter of 30 cm (12 in), and the hoof is 15 cm (5.9 in) high in males and 10 cm (3.9 in) in females.:36 The rear of each hoof is low and the fetlock is close to the ground, allowing the foot to support the animal's weight. Giraffes lack dewclaws and interdigital glands. The giraffe's pelvis, though relatively short, has an ilium that is outspread at the upper ends.
A giraffe has only two gaits: walking and galloping. Walking is done by moving the legs on one side of the body at the same time, then doing the same on the other side. When galloping, the hind legs move around the front legs before the latter move forward, and the tail will curl up. The animal relies on the forward and backward motions of its head and neck to maintain balance and the counter momentum while galloping.:327–29 The giraffe can reach a sprint speed of up to 60 km/h (37 mph), and can sustain 50 km/h (31 mph) for several kilometers.
A giraffe rests by lying with its body on top of its folded legs.:329 To lie down, the animal kneels on its front legs and then lowers the rest of its body. To get back up, it first gets on its knees and spreads its hind legs to raise its hindquarters. It then straightens its front legs. With each step, the animal swings its head.:31 In captivity, the giraffe sleeps intermittently around 4.6 hours per day, mostly at night. It usually sleeps lying down, however, standing sleeps have been recorded, particularly in older individuals. Intermittent short "deep sleep" phases while lying are characterized by the giraffe bending its neck backwards and resting its head on the hip or thigh, a position believed to indicate paradoxical sleep. If the giraffe wants to bend down to drink, it either spreads its front legs or bends its knees. Giraffes would probably not be competent swimmers as their long legs would be highly cumbersome in the water, although they could possibly float. When swimming, the thorax would be weighed down by the front legs, making it difficult for the animal to move its neck and legs in harmony or keep its head above the surface.
The giraffe has an extremely elongated neck, which can be up to 2 m (6 ft 7 in) in length, accounting for much of the animal's vertical height.:29 The long neck results from a disproportionate lengthening of the cervical vertebrae, not from the addition of more vertebrae. Each cervical vertebra is over 28 cm (11 in) long.:71 They comprise 52–54 percent of the length of the giraffe's vertebral column, compared with the 27–33 percent typical of similar large ungulates, including the giraffe’s closest living relative, the okapi. This elongation largely takes place after birth, as giraffe mothers would have a difficult time giving birth to young with the same neck proportions as adults. The giraffe's head and neck are held up by large muscles and a nuchal ligament, which are anchored by long dorsal spines on the anterior thoracic vertebrae, giving the animal a hump.
The giraffe's neck vertebrae have ball and socket joints.:71 In particular, the atlas–axis joint (C1 and C2) allows the animal to tilt its head vertically and reach more branches with the tongue.:29 The point of articulation between the cervical and thoracic vertebrae of giraffes is shifted to lie between the first and second thoracic vertebrae (T1 and T2), unlike most other ruminants where the articulation is between the seventh cervical vertebra (C7) and T1. This allows C7 to contribute directly to increased neck length and has given rise to the suggestion that T1 is actually C8, and that giraffes have added an extra cervical vertebra. However, this proposition is not generally accepted, as T1 has other morphological features, such as an articulating rib, deemed diagnostic of thoracic vertebrae, and because exceptions to the mammalian limit of seven cervical vertebrae are generally characterized by increased neurological anomalies and maladies.
There are two main hypotheses regarding the evolutionary origin and maintenance of elongation in giraffe necks. The "competing browsers hypothesis" was originally suggested by Charles Darwin and only challenged recently. It suggests that competitive pressure from smaller browsers, such as kudu, steenbok and impala, encouraged the elongation of the neck, as it enabled giraffes to reach food that competitors could not. This advantage is real, as giraffes can and do feed up to 4.5 m (15 ft) high, while even quite large competitors, such as kudu, can only feed up to about 2 m (6 ft 7 in) high. In a recent study that experimentally investigated the foraging competition between giraffes and smaller browsers, Cameron and de Tout (2007) determined that partitioning behavior was indeed occurring. Giraffes generally fed at higher levels to gain access to more leaf biomass per bite, which was not a result of differential resource allocation by the tree. However, scientists disagree about just how much time giraffes spend feeding at levels beyond the reach of other browsers, and a 2010 study found that adult giraffes with longer necks actually suffered higher mortality rates under drought conditions than their shorter-necked counterparts. This study suggests that maintaining a longer neck requires more nutrients, which puts longer-necked giraffes at risk during a food shortage.
The other main theory, the sexual selection hypothesis, proposes that the long necks evolved as a secondary sexual characteristic, giving males an advantage in "necking" contests (see below) to establish dominance and obtain access to sexually receptive females. Simmons and Scheepers (1996) claim that there are four morphological differences that exist between males and females: head and neck mass, head and neck mass increasing throughout life in males, greater increases in neck length in males proportional to leg length, and no survival value in the long neck but significant survival cost. In support of this theory, necks are longer and heavier for males than females of the same age, and the former do not employ other forms of combat. However, one objection is that it fails to explain why female giraffes also have long necks. Simmons and Scheepers (1996) give two possible explanations. The first is that past selection pressures caused elongation in both sexes and that these pressures are no longer present. Second, because sexual selection has driven male necks to be so long, female necks followed suit. Unlike elaborate feather ornaments in birds, the ossicones and necks of females are integral skeletal parts that would be coupled with increases in body size.
The most recent article addressing the debate fails to support the existence of any significant morphological difference in the heads and necks between sexes. Mitchell et al. (2013) examines the growth patterns of giraffes of both sexes and concludes that sexual dimorphism is minimal and can be attributed to variance in sex steroids.
While both hypotheses should result in longer necks, a distinction should be made between the incipient growth (origin) and maintenance of the morphological trait. The foraging hypothesis supports the origin of the trait through natural selection but is lacking in the maintenance of the trait over the last 1 million years. In comparison, sexual selection explains the evolutionary maintenance of the trait but less successfully addresses evolutionary origin, because of the necessity of the long neck at the incipient stages.
It is also important to consider neck length in the context of leg length, as it is likely that the two coevolved. Under the browser hypothesis, legs should have elongated at the same pace as necks, whereas the sexual selection hypothesis predicts neck length should increase disproportionately.
In mammals, the left recurrent laryngeal nerve is longer than the right; in the giraffe it is over 30 cm (12 in) longer. These nerves are longer in the giraffe than in any other living animal; the left nerve is over 2 m (6 ft 7 in) long. Each nerve cell in this path begins in the brainstem and passes down the neck along the vagus nerve, then branches off into the recurrent laryngeal nerve which passes back up the neck to the larynx. Thus, these nerve cells have a length of nearly 5 m (16 ft) in the largest giraffes. The structure of a giraffe's brain resembles that of domestic cattle.:31 The shape of the skeleton gives the giraffe a small lung volume relative to its mass. Its long neck gives it a large amount of dead space, in spite of its narrow windpipe. These factors increase the resistance to airflow. Nevertheless, the animal can still supply enough oxygen to its tissues.
The circulatory system of the giraffe has several adaptations for its great height. Its heart, which can weigh more than 25 lb (11 kg) and measures about 2 ft (61 cm) long, must generate approximately double the blood pressure required for a human to maintain blood flow to the brain. As such, the wall of the heart can be as thick as 7.5 cm (3.0 in). Giraffes have unusually high heart rates for their size, at 150 beats per minute.:76 In the upper neck, the rete mirabile prevents excess blood flow to the brain when the giraffe lowers its head. The jugular veins also contain several (most commonly seven) valves to prevent blood flowing back into the head from the inferior vena cava and right atrium while the head is lowered. Conversely, the blood vessels in the lower legs are under great pressure (because of the weight of fluid pressing down on them). To solve this problem, the skin of the lower legs is thick and tight; preventing too much blood from pouring into them.
Giraffes have oesophageal muscles that are unusually strong to allow regurgitation of food from the stomach up the neck and into the mouth for rumination.:78 They have four chambered stomachs, as in all ruminants, and the first chamber has adapted to their specialized diet. The giraffe's intestines measure up to 80 m (260 ft) in length and have a relatively small ratio of small to large intestine. The liver of the giraffe is small and compact.:76 A gallbladder is generally present during fetal life, but it may disappear before birth.
Behavior and ecology
Habitat and feeding
Giraffes usually inhabit savannas, grasslands and open woodlands. They prefer Acacia, Commiphora, Combretum and open Terminalia woodlands over denser environments like Brachystegia woodlands.:322 The Angolan giraffe can be found in desert environments. Giraffes browse on the twigs of trees, preferring trees of genera Acacia, Commiphora and Terminalia, which are important sources of calcium and protein to sustain the giraffe's growth rate. They also feed on shrubs, grass and fruit.:324 A giraffe eats around 34 kg (75 lb) of foliage daily. When stressed, giraffes may chew the bark off branches. Although herbivorous, the giraffe has been known to visit carcasses and lick dried meat off bones.:325
During the wet season, food is abundant and giraffes are more spread out, while during the dry season, they gather around the remaining evergreen trees and bushes. Mothers tend to feed in open areas, presumably to make it easier to detect predators, although this may reduce their feeding efficiency. As a ruminant, the giraffe first chews its food, then swallows it for processing and then visibly passes the half-digested cud up the neck and back into the mouth to chew again.:78–79 It is common for a giraffe to salivate while feeding.:27 The giraffe requires less food than many other herbivores, because the foliage it eats has more concentrated nutrients and it has a more efficient digestive system. The animal's feces come in the form of small pellets. When it has access to water, a giraffe drinks at intervals no longer than three days.
Giraffes have a great effect on the trees that they feed on, delaying the growth of young trees for some years and giving "waistlines" to trees that are too tall. Feeding is at its highest during the first and last hours of daytime. Between these hours, giraffes mostly stand and ruminate. Rumination is the dominant activity during the night, when it is mostly done lying down.
Social life and breeding habits
While giraffes are usually found in groups, the composition of these groups tends to be open and ever-changing. They have few strong social bonds, and aggregations usually change members every few hours. For research purposes, a "group" has been defined as "a collection of individuals that are less than a kilometre apart and moving in the same general direction." The number of giraffes in a group can range up to 32 individuals. The most stable giraffe groups are those made of mothers and their young, which can last weeks or months. Social cohesion in these groups is maintained by the bonds formed between calves.:330 Mixed-sex groups made of adult females and young males are also known to occur. Subadult males are particularly social and will engage in playfights. However, as they get older males become more solitary. Giraffes are not territorial, but they have home ranges. Male giraffes occasionally wander far from areas that they normally frequent.:329
Although generally quiet and non-vocal, giraffes have been heard to communicate using various sounds. During courtship, males emit loud coughs. Females call their young by bellowing. Calves will emit snorts, bleats, mooing and mewing sounds. Giraffes also snore, hiss, moan and make flute-like sounds, and they communicate over long distances using infrasound.
Reproduction is broadly polygamous: a few older males mate with the fertile females. Male giraffes assess female fertility by tasting the female's urine to detect estrus, in a multi-step process known as the flehmen response. Males prefer young adult females over juveniles and older adults. Once an estrous female is detected, the male will attempt to court her. When courting, dominant males will keep subordinate ones at bay. During copulation, the male stands on his hind legs with his head held up and his front legs resting on the female's sides.
Birthing and parental care
Giraffe gestation lasts 400–460 days, after which a single calf is normally born, although twins occur on rare occasions. The mother gives birth standing up. The calf emerges head and front legs first, having broken through the fetal membranes, and falls to the ground, severing the umbilical cord. The mother then grooms the newborn and helps it stand up.:40 A newborn giraffe is about 1.8 m (6 ft) tall. Within a few hours of birth, the calf can run around and is almost indistinguishable from a one-week-old. However, for the first 1–3 weeks, it spends most of its time hiding; its coat pattern providing camouflage. The ossicones, which have lain flat while it was in the womb, become erect within a few days.
Mothers with calves will gather in nursery herds, moving or browsing together. Mothers in such a group may sometimes leave their calves with one female while they forage and drink elsewhere. This is known as a "calving pool". Adult males play almost no role in raising the young,:337 although they appear to have friendly interactions. Calves are at risk of predation, and a mother giraffe will stand over her calf and kick at an approaching predator. Females watching calving pools will only alert their own young if they detect a disturbance, although the others will take notice and follow. The bond a mother shares with her calf varies, though it can last until her next calving. Likewise, calves may suckle for only a month:335 or as long as a year. Females become sexually mature when they are four years old, while males become mature at four or five years. However, males must wait until they are at least seven years old to gain the opportunity to mate.:40
Male giraffes use their necks as weapons in combat, a behavior known as "necking". Necking is used to establish dominance and males that win necking bouts have greater reproductive success. This behavior occurs at low or high intensity. In low intensity necking, the combatants rub and lean against each other. The male that can hold itself more erect wins the bout. In high intensity necking, the combatants will spread their front legs and swing their necks at each other, attempting to land blows with their ossicones. The contestants will try to dodge each other's blows and then get ready to counter. The power of a blow depends on the weight of the skull and the arc of the swing. A necking duel can last more than half an hour, depending on how well matched the combatants are.:331 Although most fights do not lead to serious injury, there have been records of broken jaws, broken necks, and even deaths.
After a duel, it is common for two male giraffes to caress and court each other, leading up to mounting and climax. Such interactions between males have been found to be more frequent than heterosexual coupling. In one study, up to 94 percent of observed mounting incidents took place between males. The proportion of same-sex activities varied from 30–75 percent. Only one percent of same-sex mounting incidents occurred between females.
Mortality and health
Giraffes have an unusually long lifespan compared to other ruminants, up to 25 years in the wild. Because of their size, eyesight and powerful kicks, adult giraffes are usually not subject to predation. However, they can fall prey to lions and are regular prey for them in Kruger National Park. Nile crocodiles can also be a threat to giraffes when they bend down to drink.:31 Calves are much more vulnerable than adults, and are additionally preyed on by leopards, spotted hyenas and wild dogs. A quarter to a half of giraffe calves reach adulthood.
Some parasites feed on giraffes. They are often hosts for ticks, especially in the area around the genitals, which has thinner skin than other areas. Tick species that commonly feed on giraffes are those of genera Hyalomma, Amblyomma and Rhipicephalus. Giraffes may rely on red-billed and yellow-billed oxpeckers to clean them of ticks and alert them to danger. Giraffes host numerous species of internal parasite and are susceptible to various diseases. They were victims of the (now eradicated) viral illness rinderpest.
Relationship with humans
History and cultural significance
Humans have interacted with giraffes for millennia. The Bushmen of southern Africa have medicine dances named after some animals; the giraffe dance is performed to treat head ailments. How the giraffe got its height has been the subject of various African folktales, including one from eastern Africa which explains that the giraffe grew tall from eating too many magic herbs. Giraffes were depicted in art throughout the African continent, including that of the Kiffians, Egyptians and Meroë Nubians.:45–47 The Kiffians were responsible for a life-size rock engraving of two giraffes that has been called the "world's largest rock art petroglyph".:45 The Egyptians gave the giraffe its own hieroglyph, named 'sr' in Old Egyptian and 'mmy' in later periods.:49 They also kept giraffes as pets and shipped them around the Mediterranean.:48–49
The giraffe was also known to the Greeks and Romans, who believed that it was an unnatural hybrid of a camel and a leopard and called it camelopardalis.:50 The giraffe was among the many animals collected and displayed by the Romans. The first one in Rome was brought in by Julius Caesar in 46 BC and exhibited to the public.:52 With the fall of the Roman Empire, the housing of giraffes in Europe declined.:54 During the Middle Ages, giraffes were only known to Europeans through contact with the Arabs, who revered the giraffe for its peculiar appearance.
In 1414, a giraffe was shipped from Malindi to Bengal. It was then taken to China by explorer Zheng He and placed in a Ming Dynasty zoo. The animal was a source of fascination for the Chinese people, who associated it with the mythical Qilin.:56 The Medici giraffe was a giraffe presented to Lorenzo de' Medici in 1486. It caused a great stir on its arrival in Florence. Another famous giraffe was brought from Egypt to Paris in the early 19th century. A sensation, the giraffe was the subject of numerous memorabilia or "giraffanalia".:81
Giraffes continue to have a presence in modern culture. Salvador Dalí depicted them with conflagrated manes in some of his surrealist paintings. Dali considered the giraffe to be a symbol of masculinity, and a flaming giraffe was meant to be a "masculine cosmic apocalyptic monster".:123 Several children's books feature the giraffe, including David A. Ufer's The Giraffe Who Was Afraid of Heights, Giles Andreae's Giraffes Can't Dance and Roald Dahl's The Giraffe and the Pelly and Me. Giraffes have appeared in animated films, as minor characters in Disney's The Lion King and Dumbo, and in more prominent roles in The Wild and in the Madagascar films. Sophie the Giraffe has been a popular teether since 1961. Another famous fictional giraffe is the Toys "R" Us mascot Geoffrey the Giraffe.:127 The giraffe is also the national animal of Tanzania.
The giraffe has also been used for some scientific experiments and discoveries. Scientists have looked at the properties of giraffe skin when developing suits for astronauts and fighter pilots.:76 This is because the people in these professions are in danger of passing out if blood rushes to their legs. Computer scientists have modeled the coat patterns of several subspecies using reaction–diffusion mechanisms. The constellation of Camelopardalis, introduced in the seventeenth century, depicts a giraffe.:119–20 The Tswana people of Botswana saw the constellation Crux as two giraffes – Acrux and Mimosa forming a male, and Gacrux and Delta Crucis forming the female.
Exploitation and conservation status
Giraffes were probably common targets for hunters throughout Africa.:337 Different parts of their bodies were used for different purposes. Their meat was used for food. The tail hairs served as flyswatters, bracelets, necklaces and thread.:337 Shields, sandals and drums were made using the skin, and the strings of musical instruments were from the tendons. The smoke from burning giraffe skins was used by the medicine men of Buganda to treat nose bleeds.:337 The Humr people of Sudan consume the drink Umm Nyolokh; which is created from the liver and marrow of giraffes. Umm Nyolokh often contains DMT and other psychoactive substances from plants the giraffes eat such as Acacia; and is known to cause hallucinations of giraffes, believed to be the giraffes ghosts by the Humr.   In the 19th Century, European explorers began to hunt them for sport.:129 Habitat destruction has hurt the giraffe, too: in the Sahel, the need for firewood and grazing room for livestock has led to deforestation. Normally, giraffes can coexist with livestock, since they do not directly compete with them.
The giraffe species as a whole is assessed as Least Concern from a conservation perspective by the IUCN, as it is still numerous. However, giraffes have been extirpated from much of their historic range including Eritrea, Guinea, Mauritania and Senegal. They may also have disappeared from Angola, Mali, and Nigeria, but have been introduced to Rwanda and Swaziland. Two subspecies, the West African giraffe and the Rothschild giraffe, have been classified as Endangered, as wild populations of each of them number in the hundreds. In 1997, Jonathan Kingdon suggested that the Nubian giraffe was the most threatened of all giraffes; as of 2010[update], it may number fewer than 250, although this estimate is uncertain. Private game reserves have contributed to the preservation of giraffe populations in southern Africa. Giraffe Manor is a popular hotel in Nairobi that also serves as sanctuary for Rothschild's giraffes. The giraffe is a protected species in most of its range. In 1999, it was estimated that over 140,000 giraffes existed in the wild, but estimates in 2010 indicate that fewer than 80,000 remain.
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