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The giraffe (''Giraffa'') is an African artiodactyl
mammal Mammals (from Latin language, Latin , 'breast') are a group of vertebrate animals constituting the class (biology), class Mammalia (), and characterized by the presence of mammary glands which in Female#Mammalian female, females produce milk ...
, the tallest living terrestrial animal and the largest ruminant. It is traditionally considered to be one
species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individu ...
, ''Giraffa camelopardalis'', with nine
subspecies In Taxonomy (biology), biological classification, the term subspecies refers to one of two or more populations of a species living in different subdivisions of the species' range and varying from one another by Morphology (biology), morphologi ...
. However, the existence of up to eight extant giraffe species has been described, based upon research into the mitochondrial and
nuclear DNA Nuclear DNA (nDNA), or nuclear deoxyribonucleic acid, is the DNA contained within each cell nucleus of a eukaryotic organism. It encodes for the majority of the genome in eukaryotes, with mitochondrial DNA Electron microscopy reveals mitoch ...
, as well as morphological measurements of ''Giraffa''. Seven other species are extinct, prehistoric species known from fossils. The giraffe's chief distinguishing characteristics are its extremely long neck and legs, its horn-like ossicones, and its distinctive coat patterns. It is classified under the
family In human society, family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of families is to maintain the well-being of its members an ...
Giraffidae, along with its closest extant relative, the okapi. Its scattered range extends from
Chad Chad (; ar, تشاد , ; french: Tchad, ), officially known as the Republic of Chad ( ar, جمهورية تْشَاد, link=no '; ), is a landlocked country in north-central Africa. It is bordered by Libya Libya (; ar, ليبيا, ...
in the north to
South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. With over Demographics of South Africa, 59 million people, it is the world's List of countries by population, 23rd-most populous nation a ...
in the south, and from
Niger Niger or the Niger ( or ; ), officially the Republic of the Niger, is a landlocked country in West Africa named after the Niger River. Niger is bordered by Libya Libya (; ar, ليبيا, Lībīyā), officially the State of Libya, ( ar, ...
in the west to
Somalia Somalia,; ar, الصومال, aṣ-Ṣūmāl officially the Federal Republic of Somalia, is a country in the Horn of Africa. It is bordered by Ethiopia to the west, Djibouti to the Northwest, the Gulf of Aden to the north, the Indian Oce ...
in the east. Giraffes usually inhabit
savannah A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the Canopy (forest), canopy does not close. The open canopy allows sufficient light to reach the ground to support ...
s and
woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest A forest is an area of land dominated by trees. Hundreds of de ...
s. Their food source is leaves, fruits and flowers of woody plants, primarily Acacieae, acacia species, which they browse at heights most other herbivores cannot reach. Giraffes may be preyed on by lions, leopards, spotted hyenas and African wild dogs. Giraffes live in herds of related females and their offspring, or bachelor herds of unrelated adult males, but are gregarious and may gather in large aggregations. Males establish social hierarchies through "necking", which are combat bouts where the neck is used as a weapon. dominance (ethology), 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 Vulnerable species, vulnerable to extinction, and has been Local extinction, extirpated from many parts of its former range. Giraffes are still found in numerous national parks and game reserves but estimates as of 2016 indicate that there are approximately 97,500 members of ''Giraffa'' in the wild. More than 1,600 were kept in zoos in 2010.


Etymology

The name "giraffe" has its earliest known origins in the Arabic language, Arabic word (), perhaps borrowed from the animal's Somali language, Somali name . The Arab name is translated as "fast-walker". In early Modern English the spellings and were used, probably directly from the Arabic, and in Middle English and , . The Italian language, Italian form arose in the 1590s. The modern English form developed around 1600 from the French language, French . "Camelopard" is an archaism, archaic English name for the giraffe; it derives from the Ancient Greek καμηλοπάρδαλις (''kamēlopárdalis''), from κάμηλος (''kámēlos''), "camel", and πάρδαλις (''párdalis''), "leopard", referring to its camel-like shape and leopard-like colouration.


Taxonomy

Living giraffes were originally classified as one species by Carl Linnaeus in 1758. He gave it the binomial name ''Cervus camelopardalis''. Morten Thrane Brünnich classified the genus ''Giraffa'' in 1762. The species name ''camelopardalis'' is from Latin.


Evolution

The giraffe is one of only two living genera of the family Giraffidae in the order Artiodactyla, the other being the okapi. The family was once much more extensive, with over 10 fossil Genus, genera described. Their closest known relatives may have been the extinct deer-like Climacoceratidae, climacocerids. They, together with the family Antilocapridae (whose only extant species is the pronghorn), have been placed in the superfamily Giraffoidea. These animals may have evolved from the extinct family Palaeomerycidae which might also have been the ancestor of deer. The elongation of the neck appears to have started early in the giraffe Lineage (evolution), lineage. Comparisons between giraffes and their ancient relatives suggest that vertebrae close to the skull lengthened earlier, followed by lengthening of vertebrae further down. One early giraffid ancestor was ''Canthumeryx'' which has been dated variously to have lived 25–20 million years ago (mya), 17–15 mya or 18–14.3 mya and whose deposits have been found in Libya. This animal was medium-sized, slender and antelope-like. ''Giraffokeryx'' appeared 15 mya in the Indian subcontinent and resembled an okapi or a small giraffe, and had a longer neck and similar ossicones. ''Giraffokeryx'' may have shared a clade with more massively built giraffids like ''Sivatherium'' and ''Bramatherium''. Giraffids like ''Palaeotragus'', ''Shansitherium'' and ''Samotherium'' appeared 14 mya and lived throughout Africa and Eurasia. These animals had bare ossicones and small cranial sinuses and were longer with broader skulls. ''Paleotragus'' resembled the okapi and may have been its ancestor. Others find that the okapi lineage diverged earlier, before ''Giraffokeryx''. ''Samotherium'' was a particularly important transitional fossil in the giraffe lineage as its cervical vertebrae was intermediate in length and structure between a modern giraffe and an okapi, and was more vertical than the okapi's. ''Bohlinia'', which first appeared in southeastern Europe and lived 9–7 mya was likely a direct ancestor of the giraffe. ''Bohlinia'' closely resembled modern giraffes, having a long neck and legs and similar ossicones and dentition. ''Bohlinia'' entered China and northern India in response to climate change. From there, the genus ''Giraffa'' evolved and, around 7 mya, entered Africa. Further climate changes caused the extinction of the Asian giraffes, while the African giraffes survived and radiated into several new species. Living giraffes appear to have arisen around 1 mya in eastern Africa during the Pleistocene. Some biologists suggest the modern giraffes descended from ''Giraffa jumae, G. jumae''; others find ''Giraffa gracilis, G. gracilis'' a more likely candidate. ''G. jumae'' was larger and more heavily built while ''G. gracilis'' was smaller and more lightly built. The main driver for the evolution of the giraffes is believed to have been the changes from extensive forests to more open habitats, which began 8 mya. During this time, tropical plants disappeared and were replaced by arid C4 plants, and a dry savannah emerged across eastern and northern Africa and western India. Some researchers have hypothesised that this new habitat coupled with a different diet, including acacia species, may have exposed giraffe ancestors to toxins that caused higher mutation rates and a higher rate of evolution. The coat patterns of modern giraffes may also have coincided with these habitat changes. Asian giraffes are hypothesised to have had more okapi-like colourations. The giraffe genome is around 2.9 billion base pairs in length compared to the 3.3 billion base pairs of the okapi. Of the proteins in giraffe and okapi genes, 19.4% are identical. The two species are equally distantly related to cattle, suggesting the giraffe's unique characteristics are not because of faster evolution. The Divergent evolution, divergence of giraffe and okapi lineages dates to around 11.5 mya. A small group of regulatory genes in the giraffe appear to be responsible for the animal's stature and associated circulatory adaptations.


Species and subspecies

The IUCN and most giraffe scientists currently recognise only one species of giraffe with nine subspecies. In 2001, a two-species taxonomy was proposed. A 2007 study on the genetics of giraffes, suggested six species. A 2011 study using detailed analyses of the morphology of giraffes, and application of the Species, phylogenetic species concept, described eight species of living giraffes. A 2016 study also concluded that living giraffes consist of multiple species. The researchers suggested the existence of four species, which have not exchanged genetic information between each other for 1 to 2 million years. Since then, a response to this publication has been published, highlighting seven problems in data interpretation, and concludes "the conclusions should not be accepted unconditionally". A 2020 study showed that depending on the method chosen, different taxonomic hypotheses recognizing from two to six species can be considered for the genus ''Giraffa''. That study also found that multi-species coalescent methods can lead to taxonomic over-splitting, as those methods delimit geographic structures rather than species. The three-species hypothesis, which recognises ''G''. ''camelopardalis'', ''G''. ''giraffa'', and ''G''. ''tippelskirchi'', is highly supported by phylogenetic analyses and also corroborated by most population genetic and multi-species coalescent analyses. ''G. attica'', also extinct, was formerly considered part of ''Giraffa'' but was reclassified as ''Bohlinia, Bohlinia attica'' in 1929. There are also seven extinct species of giraffe, listed as the following: * Extinction, †''Giraffa gracilis'' * †''Giraffa jumae'' * †''Giraffa priscilla'' * †''Giraffa punjabiensis'' * †''Giraffa pygmaea'' * †''Giraffa sivalensis'' * †''Giraffa stillei'' , Masai giraffe (''G. tippelskirchi'') , Masai giraffe (''G. tippelskirchi''), also known as Kilimanjaro giraffe , , The Masai giraffe (''G. c. tippelskirchi'') can be found in central and southern Kenya and in Tanzania. It has distinctive, irregular, jagged, Star polygon, star-like blotches which extend to the hooves. A median lump is usually present in males. A total of 32,550 are thought to remain in the wild, and about 100 are kept in zoos. , , , - , Rhodesian giraffe, Thornicroft's giraffe ("''G. thornicrofti''", after Harry Scott Thornicroft), also known as Luangwa giraffe, or Rhodesian giraffe , , Rhodesian giraffe, Thornicroft's giraffe ''(G. c. thornicrofti)'' is restricted to the Luangwa River, Luangwa Valley in eastern Zambia. The patches are notched and somewhat star-shaped, and may or may not extend across the legs. The median lump of males is underdeveloped. No more than 550 remain in the wild, with none kept in zoos. , ,


Appearance and anatomy

Fully grown giraffes stand tall, with males taller than females.Nowak, R.M. (1999)
''Giraffe''
Pages 1086–1089 in ''Walker's Mammals of the World. Volume 1.'' The Johns Hopkins University Press, Baltimore, USA and London, UK.
The tallest recorded male was and the tallest recorded female was tall.Dagg, A.I. and J. B. Foster (1976/1982): The Giraffe. Its Biology, Behavior, and Ecology. Krieger Publishing Company, Malabar, Florida (Reprint 1982 with updated supplementary material.) The average weight is for an adult male and for an adult female with maximum weights of and having been recorded for males and females, respectively.Owen-Smith, R.N. 1988. Megaherbivores: The Influence of Very Large Body Size on Ecology. Cambridge: Cambridge University Press. Despite its long neck and legs, the giraffe's body is relatively short. Located at both sides of the head, the giraffe's large, bulging eyes give it good all-round vision from its great height. Giraffes see in colour and their senses of hearing and olfaction, smell are also sharp. The animal can close its muscular nostrils to protect against sandstorms and ants. The giraffe's prehensile tongue is about long. It is purplish-black in colour, perhaps to protect against sunburn, and is useful for grasping foliage, as well as for grooming and cleaning the animal's nose. The upper lip of the giraffe is also prehensile and useful when foraging, and is covered in hair to protect against thorns. The tongue and inside of the mouth are covered in Taste bud, papillae. The coat has dark blotches or patches (which can be orange, Chestnut (color), chestnut, brown, or nearly black in colour) separated by light hair (usually white or Cream (colour), cream in colour.) Male giraffes become darker as they age. The coat pattern has been claimed to serve as camouflage in the light and shade patterns of savannah woodlands. When standing among trees and bushes, they are hard to see at even a few metres distance. However, adult giraffes move about to gain the best view of an approaching predator, relying on their size and ability to defend themselves rather than on camouflage, which may be more important for calves. Each individual giraffe has a unique coat pattern. Giraffe calves inherit some coat pattern traits from their mothers, and variation in some spot traits are correlated with neonatal survival. The skin underneath the blotches may serve as windows for thermoregulation, being sites for complex blood vessel systems and large sweat glands. The skin of a giraffe is mostly gray, or tan. Its thickness allows the animal to run through thorn bushes without being punctured. The fur may serve as a chemical defence, as its parasite repellents give the animal a characteristic scent. At least 11 main aromaticity, aromatic chemicals are in the fur, although indole and 3-methylindole are responsible for most of the smell. Because the males have a stronger odour than the females, the odour may also have sexual function. Along the animal's neck is a mane made of short, erect hairs. The one-metre (3.3-ft) tail ends in a long, dark tuft of hair and is used as a defense against insects. Two specimens of dwarf giraffes were found in Namibia and Uganda, named Gimli and Nigel. These dwarfs had long necks but shorter legs, key features of skeletal dysplasia.


Skull and ossicones

Both sexes have prominent horn-like structures called ossicones, which are formed from Ossification, 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 Sinus (anatomy), sinuses. 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. The giraffe's Molar (tooth), molars have a rough surface.


Legs, locomotion and posture

The front and back legs of a giraffe are about the same length. The Radius (bone), radius and ulna of the front legs are articulated by the Carpal bones, carpus, which, while structurally equivalent to the human wrist, functions as a knee. It appears that a suspensory ligament allows the lanky legs to support the animal's great weight. The foot of the giraffe reaches a diameter of , and the hoof is high in males and in females. The rear of each hoof is low and the fetlock is close to the ground, allowing the foot to provide additional support to the animal's weight. Giraffes lack dewclaws and interdigital glands. The giraffe's pelvis, though relatively short, has an Ilium (bone), 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. The giraffe can reach a sprint speed of up to , and can sustain for several kilometres. A giraffe rests by lying with its body on top of its folded legs. 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. Studies in captivity find that 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 characterised 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.


Neck

The giraffe has an extremely elongated neck, which can be up to in length, accounting for much of the animal's vertical height. The long neck results from a disproportionate lengthening of the cervical vertebrae, not from the addition of more vertebrae. Each cervical vertebra is over long. They comprise 52–54 per cent 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, perhaps because 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 strengthened 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. In particular, the Atlas (anatomy), atlas–Axis (anatomy), axis joint (C1 and C2) allows the animal to tilt its head vertically and reach more branches with the tongue. 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 characterised by increased neurological disorder, neurological anomalies and maladies. There are several hypotheses regarding the evolutionary origin and maintenance of elongation in giraffe necks. The "competing browsing (predation), browsers hypothesis" was originally suggested by Charles Darwin and challenged only 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 high, while even quite large competitors, such as kudu, can feed up to only about high. There is also research suggesting that browsing competition is intense at lower levels, and giraffes feed more efficiently (gaining more leaf biomass with each mouthful) high in the canopy. 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. Another theory, the sexual selection hypothesis, proposes that the long necks evolved as a secondary sexual dimorphism, sexual characteristic, giving males an advantage in "necking" contests (see below) to establish dominance and obtain access to sexually receptive females. 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. It has also been proposed that the neck serves to give the animal greater vigilance.


Internal systems

In mammals, the left recurrent laryngeal nerve is longer than the right; in the giraffe it is over longer. These nerves are longer in the giraffe than in any other living animal; the left nerve is over 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 in the largest giraffes. The structure of a giraffe's brain resembles that of domestic cattle. It is kept cool by evaporative heat loss in the nasal passages. 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 (physiology), 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 and it can increase its respiratory rate and oxygen diffusion when running. The circulatory system of the giraffe has several adaptations for its great height. Its heart, which can weigh more than and measures about 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 . Giraffes have unusually high heart rates for their size, at 150 beats per minute. When the animal lowers its head the blood rushes down fairly unopposed and a rete mirabile in the upper neck, with its large Cross section (geometry), cross sectional area, prevents excess blood flow to the brain. When it raises again, the blood vessels constrict and direct blood into the brain so the animal does not faint. The jugular veins 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 Esophagus, oesophageal muscles that are unusually strong to allow regurgitation of food from the stomach up the neck and into the mouth for wikt:ruminate, rumination. They have four chambered stomachs, as in all ruminants, and the first chamber has adapted to their specialized diet. The intestines of an adult giraffe measure more than in length and have a relatively small ratio of small to large intestine. The liver of the giraffe is small and compact. A gallbladder is generally present during fetal life, but it may disappear before birth.


Behaviour and ecology


Habitat and feeding

Giraffes usually inhabit
savannah A savanna or savannah is a mixed woodland-grassland ecosystem characterised by the trees being sufficiently widely spaced so that the Canopy (forest), canopy does not close. The open canopy allows sufficient light to reach the ground to support ...
s and open
woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the '' plurale tantum'' woods), a low-density forest A forest is an area of land dominated by trees. Hundreds of de ...
s. They prefer Acacieae, ''Commiphora'', ''Combretum'' and open ''Terminalia (plant), Terminalia'' woodlands over denser environments like ''Brachystegia'' woodlands. The Angolan giraffe can be found in desert environments. Giraffes browse on the twigs of trees, preferring trees of the subfamily Acacieae and the genera ''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. A giraffe eats around 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. 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. It is common for a giraffe to salivate while feeding. 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 faeces 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

Giraffes are usually found in groups that vary in size and composition according to ecological, anthropogenic, temporal, and social factors. Traditionally, the composition of these groups had been described as open and ever-changing. 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." More recent studies have found that giraffes have long-term social associations and may form groups or pairs based on kinship, sex or other factors, and these groups regularly associate with one another in larger communities or sub-communities within a fission–fusion society. Social relationships can be disrupted by proximity to humans. Masai giraffes of Tanzania live in distinct social subpopulations that overlap spatially, but have different reproductive rates and calf survival rates. The number of giraffes in a group can range from 1 up to 66 individuals. Giraffe groups tend to be sex-segregated although mixed-sex groups made of adult females and young males also occur. Female groups may be matrilineally related. In general, females are more selective than males in who they associate with in regards to individuals of the same sex. Particularly stable giraffe groups are those made of mothers and their young, which can last weeks or months. Young males also form groups and will engage in playfights. However, as they get older males become more solitary but may also associate in pairs or with female groups. Giraffes are not Territory (animal), territorial, but they have home ranges that vary according to rainfall and proximity to human settlements. Male giraffes occasionally wander far from areas that they normally frequent. Although generally quiet and non-vocal, giraffes have been heard to communicate using snorts, sneezes, coughs, snores, hisses, bursts, moans, grunts and flute-like sounds. During courtship, males emit loud coughs. Females call their young by bellowing. Calves will emit snorts, bleats, mooing and mewing sounds. During nighttime, giraffes appear to humming, hum to each other above the infrasound range for purposes which are unclear. Giraffes may also communicate visually with actions such as stamping, head tossing, and mane-waving.


Reproduction and parental care

Reproduction in giraffes is broadly polygamous: a few older males mate with the fertile females. Females can reproduce throughout the year and experience oestrus cycling approximately every 15 days. Female giraffes in oestrous are dispersed over space and time, so reproductive adult males adopt a strategy of roaming among female groups to seek mating opportunities, with periodic hormone-induced rutting behaviour approximately every two weeks. Males prefer young adult females over juveniles and older adults. Male giraffes assess female fertility by tasting the female's urine to detect oestrus, in a multi-step process known as the flehmen response. Once an oestrous female is detected, the male will attempt to court her. When courting, dominant males will keep subordinate ones at bay. A courting male may lick a female's tail, rest his head and neck on her body or nudge her with his ossicones. During copulation, the male stands on his hind legs with his head held up and his front legs resting on the female's sides. 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. A newborn giraffe is 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 "Crèche (zoology), calving pool". Adult males play almost no role in raising the young, 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 length time in which offspring stay with their mother varies, though it can last until the female's next calving. Likewise, calves may suckle for only a month 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. Spermatogenesis in male giraffes begins at three to four years of age. Males must wait until they are at least seven years old to gain the opportunity to mate.


Necking

Male giraffes use their necks as weapons in combat, a behaviour known as "necking". Necking is used to establish dominance and males that win necking bouts have greater reproductive success. This behaviour 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. 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. 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 Homosexual behavior in animals, same-sex activities varied from 30 to 75 percent. Only one percent of same-sex mounting incidents occurred between females.


Mortality and health

Giraffes have high adult survival probability, and an unusually long lifespan compared to other ruminants, up to 38 years. Because of their size, eyesight and powerful kicks, adult giraffes are usually not subject to predation, although lions may regularly prey on individuals up to . Giraffes are the most common food source for the big cats in Kruger National Park, comprising nearly a third of the meat consumed, although only a small portion of the giraffes were probably killed by predators, as a majority of the consumed giraffes appeared to be scavenged. Nile crocodiles can also be a threat to giraffes when they bend down to drink. Adult female survival is significantly correlated with gregariousness, the average number of other females she is seen associating with. Calves are much more vulnerable than adults and are additionally preyed on by leopards, spotted hyenas and African wild dog, wild dogs. A quarter to a half of giraffe calves reach adulthood. Calf survival varies according to the season of birth, with calves born during the dry season having higher survival rates. The local, seasonal presence of large herds of migratory blue wildebeest, wildebeests and plains zebra, zebras reduces predation pressure on giraffe calves and increases their survival probability. In turn, it has been suggested that other ungulates may benefit from associating with giraffes as their height allows them to spot predators from further away. Zebras were found to glean information on predation risk from giraffe body language and spend less time scanning the environment when giraffes are present. 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 Oxpecker, 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. Giraffes can also suffer from a skin disorder, which comes in the form of wrinkles, Cutaneous condition#Lesions, lesions or raw skin fissure, fissures. In Tanzania, it appears to be caused by a nematode, and may be further affected by secondary infections. As much as 79% of giraffes show signs of the disease in Ruaha National Park, but it did not cause mortality in Tarangire National Park, Tarangire and is less prevalent in areas with fertile soils.


Relationship with humans

Humans have interacted with giraffes for millennia. They were depicted in art throughout the African continent, including that of the Kiffian culture, Kiffians, Ancient Egypt, Egyptians, and Kushites. The Kiffians were responsible for a life-size rock engraving of two giraffes, dated 8,000 years ago, that has been called the "world's largest rock art petroglyph". How the giraffe got its height has been the subject of various Culture of Africa#Folklore and religion, African folktales. The Tugen people of modern Kenya used the giraffe to depict their god Mda. The Egyptians gave the giraffe its own Egyptian hieroglyphs, hieroglyph, named 'sr' in Old Egyptian language, Old Egyptian and 'mmy' in later periods. They also kept giraffes as pets and shipped them around the Mediterranean. The giraffe was also known to the Ancient Greece, Greeks and Ancient Rome, Romans, who believed that it was an unnatural hybrid of a camel and a leopard or a Panthera, panther and called it ''camelopardalis''. The giraffe was among the many animals collected and Mosaic Fragment with Man Leading a Giraffe (Art Institute of Chicago), displayed by the Romans. The first one in Rome was brought in by Julius Caesar in 46 BC and exhibited to the public. With the fall of the Western Roman Empire, the housing of giraffes in Europe declined. During the Middle Ages, giraffes were known to Europeans through contact with the Arabs, who revered the giraffe for its peculiar appearance. Individual captive giraffes were given celebrity status throughout history. In 1414, a giraffe was shipped from Malindi to Bengal. It was then Treasure voyages, 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. The Medici giraffe was a giraffe presented to Lorenzo de' Medici in 1486. It caused a great stir on its arrival in Florence. Zarafa (giraffe), Zarafa, another famous giraffe, was brought from History of Egypt under the Muhammad Ali dynasty, Egypt to Paris in the early 19th century as a gift from Muhammad Ali of Egypt to Charles X of France. A sensation, the giraffe was the subject of numerous memorabilia or "giraffanalia". Giraffes continue to have a presence in modern culture. Salvador Dalí depicted them with burning 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". 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 (franchise), Madagascar'' films. Sophie the Giraffe has been a popular teether since 1961. Another famous fictional giraffe is the Toys "R" Us mascot Toys "R" Us#Geoffrey the Giraffe, Geoffrey the Giraffe. 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 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. The Tswana people of Botswana traditionally see the constellation Crux as two giraffes – Acrux and Beta Crucis, Mimosa forming a male, and Gacrux and Delta Crucis forming the female.


Exploitation and conservation status

In 2010, giraffes were assessed as Least Concern from a conservation perspective by the International Union for Conservation of Nature (IUCN), but the 2016 assessment categorized giraffes as Vulnerable species, Vulnerable. In 1999, it was estimated that over 140,000 giraffes existed in the wild, but estimations as of 2016 indicate that there are approximately 97,500 members of ''Giraffa'' in the wild, down from 155,000 in 1985. The Masai and reticulated subspecies are Endangered species, endangered, and the Rothschild subspecies is Near-threatened species, near threatened. The Nubian subspecies is critically endangered. The primary causes for giraffe population declines are habitat loss and direct killing for bushmeat markets. Giraffes have been Local extinction, 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. , there were more than 1,600 in captivity at Species360-registered zoos. Protected areas such as national parks provide important habitat and anti-poaching protection to giraffe populations. Community-based conservation efforts outside national parks are also effective at protecting giraffes and their habitats. Private game reserves have contributed to the preservation of giraffe populations in southern Africa. The giraffe is a protected species in most of its range. It is the national animal of Tanzania, and is protected by law, and unauthorised killing can result in imprisonment. The UN backed Convention of Migratory Species selected giraffes for protection in 2017. In 2019, giraffes were listed under Appendix 2 of the Conference of the Parties to the UN Convention on International Trade in Endangered Species (CITES), which will now document international trade in giraffe parts, such as hides, bones and meat. Translocation (Wildlife conservation), Translocations are sometimes used to augment or re-establish diminished or extirpated populations, but these activities are risky and difficult to undertake using the best practices of extensive pre- and post-translocation studies and ensuring a viable founding population. Aerial survey is the most common method of monitoring giraffe population trends in the vast roadless tracts of African landscapes, but aerial methods are known to undercount giraffes. Ground-based survey methods are more accurate and can be used in conjunction with aerial surveys to make accurate estimates of population sizes and trends. Giraffes were probably common targets for hunters throughout Africa. 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. 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. The Humur, Humr people of Kordofan consume the drink Umm Nyolokh, which is prepared from the liver and bone marrow of giraffes. Richard Rudgley hypothesised that Umm Nyolokh might contain N,N-Dimethyltryptamine, DMT. The drink is said 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. Habitat destruction has hurt the giraffe. 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. In 2017, severe droughts in northern Kenya have led to increased tensions over land and the killing of wildlife by herders, with giraffe populations being particularly hit.


References


External links


Giraffe
African Wildlife Foundation
Giraffa camelopardalis
Encyclopedia of Life {{Authority control Giraffes, Articles containing video clips Fauna of Sub-Saharan Africa Herbivorous mammals Mammal genera Mammals described in 1758 Mammals of Africa National symbols of Tanzania Taxa named by Carl Linnaeus Vulnerable animals Vulnerable biota of Africa