Giraffe facts for kids
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Giraffa
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| Giraffa camelopardalis |
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A giraffe (Giraffa camelopardalis) is a mammal which lives in Africa. Giraffes and Okapi are the family Giraffidae.
Giraffes are the tallest land animals. Fully grown giraffes stand 4.3–5.7 m (14.1–18.7 ft) tall, with males taller than females. The tallest recorded male was 5.88 m (19.3 ft) and the tallest recorded female was 5.17 m (17.0 ft) tall. Giraffes have an even number of toes.
They live on the savannah, which is the African grassland, or in light woodland. They do not live in thick forests where it is difficult to see predators, such as lions, approaching.
Giraffes eat leaves from tall trees and sometimes fruit, which they can reach because of their long legs and long necks. They also feed on shrubs and eat grass. They can go without water for weeks.
Giraffes live alone or in groups. Young male giraffes form small groups until they become mature. Adult males live alone. Females form groups of 4–32 animals. When the female is close to giving birth, it leaves the group for a time to give birth to its offspring, and comes back 2-3 weeks after her baby is born.
After a pregnancy of 14-15 months, the female gives birth to usually a single baby (which is called "calf"). Giraffes give birth while standing, so the baby falls down 2 metres. Giraffe calves are already 2 m tall and weigh 50-55 kg. The calf stays with its mother for 1½ years. Young giraffes become mature when they are 4 years old, and they are fully grown when they are 6 years old.
Giraffes live around 25 years in the wild and 28 years in captivity.
Contents
Subspecies
Different authorities have recognized different numbers of subspecies, differentiated by size, coloration, coat pattern and range. Some of these subspecies may prove to be separate species, as they appear to be reproductively isolated despite their mobility. Up to nine subspecies are recognized.
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G. c. angolensis
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G. c. antiquorum
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G. c. camelopardalis
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G. c. giraffa
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G. c. peralta
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G. c. rothschildi
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G. c. thornicrofti
Appearance
A fully grown giraffe is typically 5–6 meters (16–20 ft) tall, with males taller than females. The average weight is 1,200 kilograms (2,600 lb) for an adult male and 830 kilograms (1,830 lb) for an adult female. The coat is made up of brown blotches or patches separated by lighter hair.
Each giraffe has a unique coat pattern. The patches may serve as camouflage, since they mimic the dappled combination of light and shade in savanna woodlands. They may also serve as thermal windows, being the site of large blood vessels and sweat glands. The giraffe's fur may serve as a chemical defence, as it is full of antibiotics and parasite repellents that give the animal a characteristic scent. Along the animal's neck is a brown mane made of short, stiff hairs.
The tail has a black terminal tuft and is used to swat flies away. In comparison with other animals such as deer and cattle, the giraffe has proportionally larger eyes, with which it can locate food and distant predators from its great height. Giraffes also have color vision, enabling them to recognize each other.
Skull and horns
Both sexes have prominent horns, or ossicones, formed from ossified cartilage and covered in skin. The horns are fused to the skull at the parietal bones. The appearance of the horns is a reliable method of identifying the sex of giraffes: the horns of females display tufts of hair on top, whereas those of males are larger and tend to be bald on top. There is also a median horn, which is more developed in males, at the anterior of the skull. A giraffe's skull is lightened by sinuses. However, as males get older, their skulls become heavier and more club-like, helping them become more dominant in combat.
Legs, locomotion and posture
The front legs of a giraffe are about 10% longer than its hind legs. 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. True knees exist in the hind legs. The hooves are quite large: up to 6 inches across in males and up to 4 inches across in females.
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. The apparent inflexibility of its legs give it a stiff gait when walking. When galloping, the giraffe's front and hind legs work in pairs. The animal brings its hind legs ahead of and outside its front legs. It then lifts the front legs and pushes off with the hind legs, propelling it forward. The giraffe can reach a sprint speed of up to 60 km/h (37 mph) but cannot sustain a lengthy chase.
A giraffe prefers to rest lying down with its legs folded underneath its body. To get back up, it gets on its front "knees" and swings its head up with a jerk as the front legs straighten. It then splays its hind legs and raises its hindquarters. The giraffe has one of the shortest sleep requirements of any mammal, averaging only 4.5 or 4.6 hours of sleep per day. It can sleep lying down with its neck folded and its head resting on the rump or hind leg. If it wants to bend down to drink, the giraffe either spreads its front legs or bends its "knees".
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Giraffes are assumed to be unable to swim. It has been estimated that the giraffe's proportionally larger limbs have very high rotational inertias that would make rapid swimming motions strenuous. A swimming giraffe would be forced into a posture where the neck is sub-horizontal, and since the thorax would be pulled downwards by the large fore limbs, it would not be able to move the neck and limbs synchronously in the water, as it does when moving on land. This might further hamper the animal's ability to move its limbs effectively under water. A computer simulation conducted by Scientific American suggested that, while a giraffe could float, "they would be clumsy and unstable in water". The simulation suggests that the high density of the giraffe's limb bones would make it slow and cause it to experience high drag. Furthermore, the weight of the forelimbs and shoulder would pull the front of the giraffe down, straining its neck.
Neck
The giraffe has an extremely elongated neck, which can be over 2 meters (6 ft 7 in) in length, accounting for nearly half of the animal's vertical height. The long neck results from a disproportionate elongation of the cervical vertebrae, not from the addition of more vertebrae. The cervical vertebrae comprise about 45 to 50 percent of the giraffe's vertebral column, compared with the 30 percent typical of similar large ungulates, including the giraffe’s closest extant relative, the okapi. This elongation, which occurs in large part after birth, is a 150% increase in vertebrae length over similar sized animals. The giraffe's seven elongated cervical vertebrae are strung with tendons and muscles to a shoulder hump which serves as an anchor point. This is similar to the design of a crane.
Because of its long neck, the giraffe inhales a lot of air that is not used for respiration, and the windpipe contains a mix of inhaled and exhaled air, resulting in low oxygen levels. Therefore the giraffe must breathe more regularly than expected for an animal of its size and takes more than 20 breaths a minute when resting.
There are two main hypotheses regarding the evolutionary origin 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, drove the elongation of the neck so giraffes could reach food that competitors could not. This advantage is real, as giraffes can and do feed up to 5 m, while even quite large competitors, such as kudu, can only feed up to about 2 meters (6 ft 7 in).
There is also research suggesting that browsing competition below 2 m is intense, and giraffes feed more efficiently (gaining more leaf biomass per bite) higher in the canopy. However, scientists disagree about just how much time giraffes spend feeding at levels beyond the reach of other browsers. Although giraffes can feed as low as 0.5 meters (1 ft 8 in) and as high as 6 meters (20 ft) above the ground, it appears that they most often feed at 2–4 meters (6 ft 7 in – 13 ft 1 in).
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. In support of this theory, males have proportionally larger necks than females, and males with longer, bigger necks are more successful in dominance displays and courtship behavior. However, this theory fails to adequately explain why female giraffes also have long necks.
Behavior and ecology
Habitat and feeding
Giraffes usually inhabit savannas, grasslands and open woodlands. They are most common in Acacia, Commiphora, Combretum and open Terminalia woodlands and much less common in denser Brachystegia woodland. Giraffes browse on the twigs of trees, preferring trees of genera Acacia, Commiphora and Terminalia. They also feed on shrubs and eat grass and fruit. In Southern Africa, giraffes feed on all acacias, especially Acacia erioloba. The tongue and lips are tough enough to allow them to feed on trees with sharp thorns. The giraffe's tongue is about 45 centimeters (18 in) long and prehensile, so it can grasp leaves and pull them into the mouth. A giraffe can eat 65 pounds (29 kg) of leaves and twigs daily, but can survive on just 15 pounds (6.8 kg).
During the wet season, food is abundant and giraffes disperse widely, but during the dry season they need to congregate around evergreen trees and bushes. The giraffe uses its lower incisor teeth to "comb" leaves from trees while browsing. As a ruminant, it 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. This process is usually repeated several times for each mouthful.
The giraffe requires less food than typical grazing animals, because the foliage it eats has more concentrated nutrients, and it has a more efficient digestive system. Compared with domestic cattle, giraffes have a relatively short small intestine and a relatively long large intestine, giving it a small ratio of small to large intestine. The giraffe can survive without water for extended periods. When water is available, it may drink at intervals of three days or less. Giraffes can also get water from green leaves, especially when covered in dew.
Giraffes have great effects on the trees that they browse on, keeping young trees short for a year longer than usual and forming waistlines around trees whose tops are unreachable. Browsing by giraffes also gives trees a globular or hourglass shape and keeps bushes down to less than a meter. Feeding periods peak during the first and last hours of daylight. In between those hours, a giraffe may pass the time standing and ruminating. Rumination is the dominant activity during the night, when it is mostly done lying down.
Social structure
While giraffes are usually found in groups, the composition of these groups is more fluid than in other social ungulates. They have few strong social bonds, and aggregations usually disband every few hours, although calving groups can last weeks or months.
For research purposes, a "group" has been defined as "a collection of individuals that are less than a kilometer apart and moving in the same general direction." Giraffe groups usually consist of just a few members, although 40 or more occur on occasion.
Adult males tend to be solitary. Female giraffes associate in groups of roughly a dozen, occasionally including a few younger males. Calves and subadults are rarely alone. Subadult males, in particular, are gregarious and may engage in playfights. Giraffe groups with young tend to feed in more open areas, presumably to make it easier to detect predators, although it may reduce their feeding efficiency.
Although generally quiet and non-vocal, giraffes have been heard to communicate with various sounds. Courting males emit loud coughs. Females call their young by whistling or bellowing. Calves bleat, moo or make mewing sounds. Giraffes also grunt, snort, hiss, make strange flute-like sounds, and communicate over long distances using infrasound. To produce an infrasound signal, a giraffe usually lowers its chin and then quickly raises it.
Birthing and parental care
Giraffe gestation lasts between 400 and 460 days, after which a single calf is normally born, although twins occasionally occur. The mother gives birth standing up, and both amniotic sac and umbilical cord usually break when the newborn falls to the ground. A newborn giraffe has a fragile neck and it is thus important that its legs break the fall. A newborn giraffe is about 1.8 meters (5.9 ft) tall. Within a few hours of birth, the calf can run around and is indistinguishable from one a week old; however, for the first two weeks, it spends most of its time lying down, guarded by the mother. Their coat pattern provides camouflage when they are hiding. The horns, which have lain flat since it was in the womb, become erect within a few days.
Mothers with calves will gather in nursery herds, usually consisting of two or more infants and/or juveniles and their mothers moving or browsing together. Mothers in such a group may sometimes leave their calves with one female while they travel to other areas. This is known as a "calving pool". Males play almost no role in raising the young. The young are vulnerable to predators.
A mother giraffe will stand over her young and kick at a predator that comes near. Giraffes only defend their own young; they form calving herds for selfish reasons. A mother has a strong maternal bond with her calf, lasting until her next calving. Calves suckle for 13 months and continue to associate with their mothers for another 2–5 months.
Necking
Male giraffes use their necks to hit each other in combat, a behavior known as "necking". Necking is used to establish dominance and can occur at low or high intensity. In low intesity necking, the combatants gently rub their heads and necks together and lean heavily against each other, while flapping their ears and rubbing shoulders, perhaps to assess their comparative weights. The winner of such a bout is the male that can hold itself more erect.
Mortality
Because of their size, adult giraffes are almost invulnerable to predation. Calves, on the other hand, are preyed on by lions, leopards, spotted hyenas and wild dogs. Lions are capable of killing adult giraffes if they can make them fall over and then secure a bite on the throat or nose. In Kruger National Park, giraffes of any age are an important food source for lions.
Nile crocodiles may also take giraffes when they bend down to drink. A giraffe can defend itself with powerful kicks which can kill a predator when well-placed. Some parasites also feed on giraffes. Ticks are known to infest them. Giraffes have mutual relationships with red-billed and yellow-billed oxpeckers, which clean them of ticks and alert them to danger. A quarter to a half of giraffe calves reach adulthood. Maximum lifespan is around 25 years in the wild and 28 years in captivity.
Relationship with humans
Cultural significance
Giraffes were commonly depicted in the rock and cave art of prehistoric Africa. Some of the earliest of these pictures were made by the palaeolithic Kiffian people, who lived around 8000 BC in modern-day Niger. The Kiffian were responsible for a life-size rock engraving of two giraffes, which has been called the "world's largest rock art petroglyph".
The Ancient Egyptians commonly depicted giraffes in tomb paintings and kept them as pets. The Egyptians shipped giraffes from East Africa and exported them from Alexandria to ports around the Mediterranean. Giraffes were also known to the Ancient Greeks and the Ancient Romans, who referred to them as camelopardalis, a name thought to have derived from the belief that the giraffe was an unnatural cross between a camel and a leopard. The giraffe was among the many animals collected and displayed by the Romans as exotic spoils of conquered lands. The first giraffe in Rome was imported by Julius Caesar and exhibited to the public.
With the fall of the Roman Empire, the people of Europe were no longer able to keep and display giraffes. During the Middle Ages, giraffes were mostly forgotten by Europeans, except in legends from Arab travelers. Arab prophets and poets considered the giraffe the "queen of beasts" for what they saw as its delicate features and fragile form. Eastern sultans prized them as special pets. In 1414, a giraffe was taken from Somalia to China and placed in a Ming Dynasty zoo. Its arrival caused a sensation, as it was thought to be 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, being reputedly the first living giraffe to be seen in Italy since antiquity. Another famous giraffe, called Zarafa, was brought from Egypt to Paris in the early 19th century. Zarafa also caused a sensation and was the subject of numerous memorabilia or "giraffanalia".
Giraffes continue to have a presence in modern culture. Salvador Dalí depicted them in some of his surrealist paintings, most often in various states of conflagration. Dali considered the giraffe to be a symbol of masculinity, and a flaming giraffe was meant to be a "masculine cosmic apocalyptic monster". Giraffes have also appeared in animated films, as minor characters in The Lion King and Dumbo, and in more prominent roles in The Wild and in the Madagascar films. Sophie the Giraffe is a popular teether that has been a favorite toy for babies since 1961. Another famous fictional giraffe is the Toys "R" Us mascot Geoffrey the Giraffe.
Images for kids
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The extinct giraffid Samotherium (middle) in comparison with the okapi (below) and giraffe. The anatomy of Samotherium appears to have shown a transition to a giraffe-like neck.
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Closeup of the head of a northern giraffe
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Right hind leg of a Masai giraffe at San Diego Zoo
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Reticulated giraffe bending down to drink in Kenya. The circulatory system is adapted to deal with blood flow rushing down its neck.
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Female Angolan giraffe with calf
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Painting of a giraffe imported to China during the Ming dynasty
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Endangered West African giraffe near Koure, Niger
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See also
In Spanish: Giraffa para niños
 | Joan Baez |
 | Gloria E. Anzaldúa |
 | Vicente T. Ximenes |
 | Mario G. Obledo |
