Facts About Giraffes: Height, Necks and Heart

Giraffes are the tallest land animals, instantly recognisable by their long necks and patchwork coats. They have fascinated people for centuries, and research continues to reveal how they live.

Key takeaways

• Adult giraffes can reach around 5 to 5.5 metres in height.
• Like most mammals, they have seven neck vertebrae, but each is very elongated.
• Their strong hearts and special blood vessels manage blood flow to the head.
• Each giraffe has a unique coat pattern.
• Genetic studies suggest there may be more than one species, though experts differ.

Towering height

Males can reach around 5.5 metres, and females are a little shorter. A newborn calf is already about 1.8 metres tall and falls to the ground during birth, then stands within an hour. The long legs alone are taller than many humans. Giraffes live in the savannas and woodlands of Africa, south of the Sahara.

Seven bones in the neck

A giraffe's neck is about two metres long, yet it contains the same number of vertebrae as a human or a mouse: seven. Each vertebra is simply much longer, around 25 centimetres. This is a nice example of how evolution modifies existing structures instead of creating new ones.

A heart under pressure

To pump blood up to the brain, against gravity, a giraffe needs high blood pressure, roughly twice that of humans. Its heart is large and muscular, and the walls of its blood vessels are thick. Valves and a network of vessels in the neck help prevent too much blood from rushing to the brain when the giraffe lowers its head to drink, and special adaptations in the legs help limit fluid build-up.

Feeding

Giraffes browse the leaves of trees, especially acacias, using their prehensile, dark purple tongues that can reach around 45 centimetres in length. The tongue and lips are tough enough to handle thorns. A giraffe may spend most of the day eating and can get much of its water from leaves, though it drinks when water is available. Drinking requires splaying the front legs wide or bending the knees.

Sleep and social life

Giraffes sleep very little, often only for short periods totalling a few hours a day, and mostly standing or lying with their necks curved back. They live in loose groups that change in size and composition, called towers when they gather. Males sometimes fight by swinging their necks and heads at each other, a behaviour called necking.

Patterns and camouflage

Each giraffe has a unique pattern of patches, like a fingerprint, although patterns are similar within a family. The patches may help with camouflage among dappled light and shade, and they may help regulate temperature, according to some research.

How many species?

For a long time, scientists classified all giraffes as one species with several subspecies. In 2016, a genetic study suggested there might be four distinct species, which the Giraffe Conservation Foundation and some scientists accepted, while the International Union for Conservation of Nature currently recognises one species with several subspecies. Researchers continue to debate the best classification.

Conservation

Giraffe numbers have dropped significantly in recent decades because of habitat loss, poaching and conflict. The IUCN lists giraffes as vulnerable, and some subspecies are endangered. Conservation work includes protecting habitat, monitoring populations and working with local communities.

How did the long neck evolve?

Scientists have proposed several explanations. The classic idea is that a longer neck let giraffes reach leaves that shorter competitors could not, especially during dry seasons when food was scarce. Another hypothesis suggests that long necks evolved through competition between males, because males with longer, stronger necks win more necking contests and gain mating opportunities. Evidence supports parts of both ideas, and some researchers argue that neither fully explains the fossil record. Related fossil animals show a range of neck lengths, and the okapi, the giraffe's closest living relative, has a short neck and a similar body plan, which helps researchers compare.

Life cycle

Females are pregnant for around fifteen months and usually give birth to a single calf while standing, so the newborn drops about two metres to the ground. Calves can stand and walk within an hour and may run with the herd within a day or so. Young giraffes are vulnerable, and in some areas many do not survive their first year. Calves are often left in groups while mothers feed, sometimes watched over by one adult. In the wild, giraffes typically live for about twenty to twenty-five years.

Predators and defence

Lions are the main predator of adult giraffes, and hyenas, leopards and crocodiles also threaten calves. A giraffe's height gives it a long view and early warning, and it can run at speed over short distances. Its main defence is a powerful kick, strong enough to injure or kill a predator. Giraffes often feed in loose groups, and when one raises its head to look at something, others tend to notice and follow its gaze.

Giraffes in history and culture

Giraffes appear in ancient Egyptian art and have been kept as exotic gifts by rulers for centuries. In 1414, a giraffe from East Africa was brought to China by the Ming dynasty treasure fleet and was celebrated as a qilin, a mythical creature associated with good fortune. In Europe, giraffes were rare and amazing sights until the nineteenth century. Today they appear in many African cultures, and their patterns inspire art and design.

Why numbers are falling

Giraffe numbers have dropped significantly across much of Africa over roughly the last three decades, in some places by a third or more according to conservation assessments. Causes include loss of habitat as land is cleared for farming and settlement, illegal hunting, and conflict. Some local populations are stable or growing thanks to protected areas and community conservation, and projects have moved giraffes to new locations to rebuild populations.

Frequently asked questions

Do giraffes make sounds?

They are mostly quiet, but they can grunt, hiss and make low humming sounds, some at frequencies hard for humans to hear.

How fast can giraffes run?

They can reach about 50 kilometres per hour in short bursts.

Are giraffes related to horses?

No. They belong to the family Giraffidae, whose closest living relative is the okapi.

How long is a giraffe's pregnancy?

Around fifteen months, one of the longest among land mammals after elephants. Mothers usually have one calf at a time.

Can giraffes swim?

Giraffes are rarely seen in deep water, and their long legs and heavy bodies are thought to make swimming difficult. They often walk across shallow rivers, but there is little direct evidence of how they cope in deep water.

Why do giraffes have dark tongues?

A common explanation is that the dark colour protects the tongue from sunburn during long periods of feeding with the tongue exposed. This is a plausible idea but not firmly proven.

Sources and further reading

• Giraffe (Wikipedia)
• Giraffe Conservation Foundation