Let’s face it — I have had a love and fascination for giraffes. I find them to be the most incredibly absurd and yet beautiful creatures to look at, whilst also giving off such a gentle and calming energy. I have found myself on countless occasions out in the bush with guests on their first game drive as they excitedly chat, talk over each other and shift around in the vehicle, scanning for animals. Often there are remnants of the mania and stress of the city and you can almost hear everyone’s minds ticking behind you. But find a herd of giraffes lazily feeding on a grassy crest, all eye lashes and long legs and the whole vehicle falls into silence and stillness. Firstly, I think because they are so crazy to look at, every other thought disappears as you attempt to wrap your head around how something so strange could exist but there is also just an undeniable serenity that they exude. Not only are these animals fun to look at though, they’re fun to learn about too.
NAME: The giraffe’s scientific name, Giraffa camelopardalis, comes from the ancient Greeks’ belief that it looked like a composite creature, a camel wearing a leopard’s coat.
HEIGHT: The giraffe is the tallest mammal in the world. Female giraffes stand at about 4, 5m while males are about 5-6m tall. A giraffe’s legs alone are taller than many humans—about 1, 8 meters/6 feet.
BIRTH: Giraffes have big babies that are born weighing about 100 kg. Even new-born babies are taller than most humans and stand at about 2 meters tall. Female giraffes give birth standing up and their young endure a rather rude welcome into the world by falling more than 5 feet (1, 5 meters) to the ground.
SLEEP: Giraffes only spend between 10 minutes and two hours asleep per day. They have one of the shortest sleep requirements of any mammal. Typically giraffes also rest standing up. Although they would probably prefer to sit down to rest, this places them in a rather vulnerable position because their powerful kick and ability to see a large area around them are their strongest defences against predators.
SPEED AND SELF-DEFENCE: Despite their size and fairly placid gait, giraffes can move incredibly fast. Because of the size of their gait (they can cover 4, 5m or 15 feet with each step), they cover a lot of distance without much effort. Even a leisurely walk gives it a speed of 16 kilometres/ 10 miles per hour. The fast and surprisingly graceful gallop of a giraffe can easily outpace a human, and even many horses. Its top recorded speed is a whopping 56 kilometres/35 miles per hour. Giraffes are well-versed in the art of self-defence, to the point where even lions only dare to attack them in large groups (and even that is fairly uncommon). Giraffe legs are incredibly powerful and each of them ends in a hard, sharp, 30-centimetre/12 inch hoof. A giraffe can kick in any direction and in a manner of ways, and its kick can not only kill a lion, but has even been known to decapitate it.Unsurprisingly, very few predators bother an adult giraffe.
MOUTHS: Even giraffes’ tongues are huge. They are up to 45 cm long and are specially adapted to allow giraffes to forage on incredibly thorny but highly palatable trees, such as Acacias. Their tongues and upper lip are also prehensile, which means that they work much like a hand or like an elephant’s trunk, dextrously wrapping around leaves and flowers. Their tongues are coloured bluish-black, which helps to protect them from sunburn because it spends so much of its day outside of its mouth feeding. They also produce incredibly sticky saliva so that should they eat a thorn, it slips down their oesophagus without doing any damage. The insides of the mouth, along with the lips and the tongue, are completely covered with hard, tough, finger-like papillae to protect it from thorns and nasty gashes.
HEARTS: Because of their unusual shape, giraffes have the difficulty of having to get blood to their heads, very far above the ground. One of the ways around this is to have an enormous heart, which weighs about 11 kilograms or 25 pounds and measures at 60cm or 2 feet. The result is also a blood pressure that is almost double that of humans. To accommodate for this the artery walls have extra elasticity and to prevent the blood from rushing too quickly back down the neck again, the jugular veins in the neck partially contract to restrict return flow.
BLOOD PRESSURE: Of course, this high blood pressure, combined with the effect of gravity on such a tall body, would also be a problem for the giraffe’s legs. The animal would bleed profusely from any cut, and there is a very real danger of blood pooling in the lower extremities. To combat this, the skin on the giraffe’s legs is extremely tough, and tightly fitted by way of a firm inner fascia to prevent blood pooling. This has been studied by NASA scientists developing the special ‘gravity-suits’ worn by astronauts to help maintain correct circulation while in space. Weightlessness has always posed a number of problems to the human body. One of the most significant issues is the weakening of leg veins. Since the blood flows differently in space, the circulatory system of the legs doesn’t have to put in so much work in order to pump the blood back up. The veins get lazy, thin, and weak, which can pose serious problems when returning to Earth.
Giraffes have provided a solution to this problem. Baby giraffes learn how to stand almost immediately upon birth, thanks to their rapidly inflating leg veins. When NASA observed this, they were able to create the Lower Body Negative Pressure Process. It’s a device that consists of an airtight tube that seals around the astronaut below the waist and applies vacuum pressure, thus rapidly expanding the leg veins and making blood rush into the legs and pelvic area. When this pressure is applied at regular intervals, the astronaut’s leg veins stay in shape. To prevent excess bleeding, the blood vessels in the giraffe’s legs also run deep (away from the skin’s surface), and those capillaries that do reach the surface are very narrow, with blood cells only one third the size of ours. Additionally, these smaller blood cells allow for faster absorption of oxygen, ensuring a good supply to the extremities of such a large animal.
DRINKING: One of the most vulnerable times for a giraffe is when it needs to drink and so they have developed the ability to gain most of their water content from the leaves that they eat. These animals however do have to drink every now and again, which with such a long neck can provide obstacles. When it lowers its head, all that high pressure blood would likely rush downhill (further assisted by gravity) and blow out the delicate blood vessels in the brain and eyes—if it weren’t for a series of clever mechanisms working in co-ordination with one another. When the head is lowered, special shunts in the arteries supplying the head restrict blood flow to the brain, diverting it into a web of small blood vessels (the rete mirabile or ‘marvellous net’). This network of vessels near the brain gently expands to accommodate the increased local blood pressure. Valves in the jugular veins also prevent returning blood from flowing backward while the head is lowered. All of this is controlled by a complex series of mechanisms that constantly monitor the pressure in the blood vessels and make whatever adjustments are needed to ensure that the proper pressure is maintained in all situations. This means that even if the giraffe lifts its head up quickly mid-drink, proper blood supply is maintained to the brain.
SPECIES: Scientists have for a long time held the belief that there was only one species of giraffe, split into about nine subspecies. New research, just released however suggests that four groups of giraffes have not cross-bred and exchanged genetic material for millions of years.
Those four species include:
- southern giraffe (Giraffa giraffa),
- Masai giraffe (G. tippelskirchi),
- reticulated giraffe (G. reticulata)
- northern giraffe (G. camelopardalis), which includes the Nubian giraffe (G. c. camelopardalis) as a distinct but related subspecies.
This suggests that each species is adapted for a specific environment or diet – a question that is the subject researchers are now turning to.
Although giraffe numbers are not considered a problem by most conservation groups, they have declined by about 40% in the last 15 years, a recent BBC report stated recently. Now that we know that these animals cannot just be lumped into one species group, this may change how we view the vulnerability of their numbers and proves how much there is still to learn about this iconic species of the African bushveld.