The Southern Giraffe
This iconic ungulate of the African savanna needs very little introduction and is widely regarded as the most common species that guests request to see when visiting the Kruger National Park. Whilst the Big 5’s reputation precedes itself and in truth with most guests not getting correct, there is never any uncertainty as to the Giraffe.
As the names suggest the Southern Giraffe or Southern African Giraffe occurs in the southern tip of African and more specifically Northern South Africa, Botswana and Zimbabwe. Whilst we only have a single sub-species found in the South African and the Kruger National Park, the Giraffe Conservation Foundation (GCF) recognises 9 sub-species spread across the African continent as follows:
African Giraffe Sub-Species:
- Maasai Giraffe (Giraffe camelopardilis tippelskirchi) – Kenya and Tanzania
- West African (Giraffe camelopardilis peralta) – Angola to Nigeria
- Southern Giraffe (Giraffe camelopardilis giraffe) – South Africa, Botswana
- Reticulated Giraffe (Giraffe camelopardilis reticulate) – Kenya, Tanzania
The Origin of the name
What many people don’t know is that long before the colonisation of Africa by the Empires of Europe during the 1800’s, the Arab traders and sea merchants had been finding trade routes into the African sub-continent via present day countries like Kenya and Tanzania as far back as the early 1400’s. These early traders brought with them an appetite for Africa’s many wonders and already began to share with the world its unique treasures such as skins, ivory and precious minerals. It was from these early voyages that Zarafa, the “fast and graceful walker” was encountered by the Arab traders and the word then evolved from Anglo-Germanic to modern name Anglo-Saxon being Giraffe. In South Africa the early Dutch pioneers (todays Afrikaans culture) named it Kameelperd which originated form the Latin Camelopardis meaning “camel leopard” because of the resemblance to that of a Camel with a Leopard’s spots. The first sighting of Giraffe in South Africa was recorded in 1663 by Pieter van Meerhof on a expedition along the south west coast of today South Africa albeit these animals would have long been roaming the interior savanna. It’s merely because the early pioneers only ventured deeper into central South Africa in the early 1800’s and explored the Kruger National Park region during these period that Kruger’s Giraffe would have been encountered.
One of our favourite names for the Giraffe is offered to us by the Zulu nation (one of South Africa’s 11 official languages) who call it iNdlulamithi , meaning the one who is taller than the trees.
Southern African Giraffe Dimension’s and Characteristics
They are members of the Order Ruminantia meaning that they have a 4-chambered stomach, chew the cud and as such ruminate.
A Male Giraffe weighs between 950 – 1,500kg whilst a female will only weigh between 650 and 950kg. The males reach a shoulder height of 3,5m and total height of 6m whilst the females have a shoulder height of 3m and total height of 4,7m.
Baby Giraffe Calf
The females have 4 inguinal teats between their hind legs and a gestation period of 15 months. A newborn baby Giraffe is born with a weight of 90-100kg and at a height of 1,5meters. Being born in a pre-cocial state (developed) the baby is able to take to its feet and stand within an hour of being born and is fairly mobile within 2 hours of birth. This is genetic herbivore response as they need to remain mobile and able to deal with the threat of carnivores. A young Giraffe Calf experiences rapid growth at nearly 1cm per day. At birth the Giraffes neck represents a sixth of its total length but within 4 years it will be a third of the body’s length.
During its first few weeks the baby Giraffe will remain very close to its mother, suckling regularly and then sitting down nearby as she feeds. In most cases the mother is never more than 200m away from the young calf. As the young calf develops the mother will move up to 3km away at a time but never be away for longer than 4 hours. This is however not done is isolation as there are usually other females with young calves that create “nursery effect” and so young calves usually share each others company but not in the typical playful manner that you see with many other species. Calves are usually fairly serious and aren’t often seen playing around with each other. A young calf’s diet is 90% milk but they will browse small amounts of plant matter in the first month and finally being weaned around a year. Young calves are considered sexually mature from between 12 to 16 months with the young males leaving their mother after 15 months of age. Giraffe calf mortality is particularly high under 18 months of age. Approximately 50% survive their first year in the Kruger National Park. We have encountered on more than one occasion having found a young month old Giraffe calf only to find the next day that its carcass was being fed on by Lion or Spotted Hyena. What is impressive is the drop in mortality rate from 50% in year one to 8% in year two and 3% in year three. Their impressive size, kick and vigilant gaze all helping it to reach adult maturity at 7 years of age. Giraffes will live to approximately 25 years but this is dependent on availability of food and water as well as predator density in a region.
Habitat and Feeding
Giraffe are found across Southern Africa in a wide variety of savanna from semi-arid and dry to subtropical savanna of the Kruger National Park. They favour areas of open savanna with grassland scrub and thorn trees (acacia / vechellia). In the Kruger National Park we find the highest Giraffe populations occurring in the Central region below the Olifant’s River heading south towards the Crocodile river on the Parks southern boundary.
Giraffe are fairly selective feeders but they are adaptable and have been documented to utilize nearly 50 species of flora extensively in the Kruger National Park. Two specific flora families that they favor are the thorny Acacia as well as Combretum (Bushwillow). Whilst they mainly feed on the leaves and small twigs of a tree or bush they also enjoy buds, flowers, seedpods and fruits of specific trees. Giraffe have been documented to feed on grass and herbs but this is less than 5% of their dietary requirement and would very specific to region and perhaps climatic conditions. As with most African mammals in the winter’s months they will consume more hard woody vegetation as a result of availability.
Giraffe will spend anywhere between 16 and 20 hours of the day feeding with 70% of that during the day light hours. As with all mammals in the Kruger National Park the feeding durations increase across the winter months, as the game needs to travel further daily to access adequate resources. Giraffe will eat between 25 and 35kg of food in a day and consume at a level that’s 1,5m above the ground. Giraffe are able to draw most of the moisture required from their browse and only visit the waterhole every 2 to 3 days consuming up to 12 litres per drinking session over the winter months and nearly as much as 40 liters of over the hot summer months.
An unusual aspect of the Giraffes diet is the occasional bone. This is a dietary craving that is present in a few other herbivores and is know as “osteophagia”. This is considered to be the supplementation of calcium and phosphorous. A study conducted in 2008 by the University of Pretoria’s faculty of Veterinary science, asked the question if this behaviour did indeed provide them with satisfactory amounts to accommodate their requirement. What was evident was the increased gnawing of bones from April each year, when the Acacia species starts loosing its leaves, all the way through to October when they again began to shoot. The Giraffes calcium requirement is formidable as a result of its large skeletal structure and of course long neck. The daily attrition of its skeletal frame does require a lot more supplementation than most. Through analysing of Giraffe and Buffalo bones across various sites in the Kruger National Park, Park researches discovered that the calcium and phosphorous level required to support the Giraffes frame were 2 to 3 times more than that of the Buffalo. As a result of this requirement they have had to come up with meaningful alternative in their browsing. In its first year of life, a young giraffe is receiving roughly 7 grams of calcium daily in the form of moms milk but thereafter will turn to their browse matter. As preferred species to feed on, Giraffe of course love Acacia species which provide some of the highest levels of calcium available. Acacia legumes offer about 3 times as much calcium as the grasses do.
An evolutionary masterpiece, the Giraffe captures our imagination with its long legs and neck but there is so much more to this animals physiology that is incredibly amazing. We always ask our guests, “apart from being the tallest mammal and having an impressive presence, have you ever though of how this animals body has evolved to ensure it can survive out on the African plain ?” or “have you ever considered how the blood is pumped 6 meters up into the air ?”. These are of the sort of questions that really start to open ones eyes as to how this elongated mega-herbivore has had to physically evolve so that it can function in the Savanna. In order to understand the journey of the giraffe and answer the question around “ how the Giraffe got its long neck?”, we need to go back in time to the origins of this species and understand its DNA and how these unique changes occurred.
The mysterious history of the Giraffe’s past does leave us a few clues and if we follows these science does reveal that a giraffe in its original form is of course a true ruminant with a 4 chambered stomach and was also, as is today, a even-toed ungulate. Using these characteristics today, science is able to trace back the lineage some 50 or so million years but the lineage is far from obvious. Looking back this far takes us to period know as the Eocene era (50mil years ago). During this time the Giraffids, a family of which the Giraffe and the Okapi were the only living members, seems to have evolved from a 3 meter tall species of Deer that roamed across Europe and Asia. Within its evolutionary cycle this species moved away from its Deer-like origin some 25 million years ago and developed longer legs and traded its antlers for ossicones ( bone covered in skin ). It was only between 15 and 10 million years ago that this species started to look anything like our modern day species with the first recognisable species being Canthumeryx syrtensis. This species then gave rise to the Okapi and Giraffes four intermediate species of which the closest form Bohlinia had its fossilised remain uncovered in Greece and dated back some 8 million years. History tells us that this species wondered deep into Asia and North India but died off some 4 million years ago as a result of climatic conditions, however the modern day Giraffe entered Africa some 7 millions years ago and also slowly died off but not before establishing the modern day genus that gave rise out of East Africa some 1 million years ago.
Today’s modern day Giraffe is the fore-bearer of some ingenious advancements and adaptations. Its movement south down the African continent meant that this species had to adapt to the changing biome conditions and develop in such a way to take advantage of the new Savanna environment. As a result of the “need to feed”, its already enhanced browsing range evolved into an even longer elongated tool giving it access and exclusivity to the far reaches of the many Savanna flora species.
The Giraffes neck, heart and hide
Surprisingly this long, extended and almost disproportionate tool has the same number of cervical vertebrae as you and I. With 7 vertebrae the difference is of course the size and each of these vertebrae, which measures around 30cm each. This long neck that will measure in at a 3rd of its body once it reaches maturity at the age of 4 years. Of course there has always been the question “Does the Giraffe get dizzy when it drink ?”, a good question but an even better adaption by the Giraffe. Within the Giraffes neck there are specialized neck arteries that are able to regulate blood flow and pressure by dilation and contraction as a result of modified capillaries. Whilst the heart is the largest of any cloven hoofed species at a diameter of 45cm, the left ventricle works in tandem with the neck arteries to circulate the blood. Together with the Giraffe having the thickest hide of all living mammals it is able to create a blood pressure of 280/180 or equal to that or roughly 35PSI were as a human only generates 12 PSI at a pressure of 120/80. This is very high pressure for Giraffe so they have further developed a fine net of veins that surround the brain which is know as the rete mirabile or “extraordinary net” which is able to then lower the pressure again and regulate flow around the brain. It is believed that this is potentially gravity induced so as the Giraffe lowers its head to drink, these vessels expand to accommodate the additional blood flow and then again contract when it raises its head. This all works together to ensure that at no point the Giraffe blacks-out whilst going through its daily habits.
A Background to Giraffe in the Kruger National Park
Giraffe occur through out the Park but the greatest populations being found in the central and southern region where they have access to their favourite food source the Knob-Thorn tree (Acacia nigrescens). They are also found in the mountain bushveld around Berg-en-Dal camp but are not well represented through the thick Mopane bush of the North and neither the far Northern Sandveld around Punda Maria. The central region between Olifant’s camp and Tshokwane outpost has the highest populations with roughly 7 Giraffe per 10sqm. Kruger’s last available census (2010-2011) indicates that the current population was then between 6,800 and 10,300 animals.
Some fascinating research was conducted in the Kruger during the 90’s by Johan du Toit who aimed to focus on Giraffe and their feeding habits and made specific comparison against two other species in that of Steenbok, Impala and Kudu. Using a real time data system he calculated the number of times each species was feeding and at what specific height and then compared the data only to find that indeed Giraffe were able to browse 90% of the time at a exclusive height that did offer them a genuine niche in the savanna amongst other antelope. Regarded as a successful piece of research, the data did align with the initial proposal that the Giraffe’s neck was a evolutionary response to out compete other species of browsing at the higher canopy levels. There was also however an alternative school of thought by British zoologist, Chapman Pincher who suggested that it wasn’t the Giraffe’s long neck that was the evolutionary masterpiece but rather the long forelegs which allowed it to escape predators, and that the neck followed there after as a means to allow it to reach the ground to drink water. The above theory was fairly well posed until Kruger’s researchers tried to better understand the level of predation by Lions as it was initially thought that Giraffe made up a very low percentage.
In an extensive analysis of carcasses found in the Kruger between 1933 and 1946 and then again between 1954 and 1966, the Parks leading Biologist, Tol Pienaar, found that of these 46,181 carcasses assessed, only 675 and been Giraffe which were confirmed Lion kills. This essentially meant that only 2% of the prey had been made of Giraffe. In a follow up analysis between 1966 and 1968, Tol Pienaar listed 108 Giraffes that had been killed by Lions. In further studies between the central and souther regions, it was noted that in the Giraffe dense central region, Giraffe meat formed 43% of the Lions food intake whilst in the southern region it made up 32%. Despite the relatively high kill rate, Giraffe are still only an alternative prey source but it does confirm their place at the Lions table.
A few interesting Giraffe Facts :
- A Large Giraffe consumes approximately 34kg of browse per day.
- In the summer Giraffe drink between 38l and 48l of water per day depending of their size.
- Over a short distance a Giraffe can accelerate to 55km/h.
- Giraffe cannot swim and are hardly ever seen waling through water.
- Giraffe are the only animals born with horns. They are roughly 25mm at birth and fold backwards.
- Giraffe home ranges cover 25km/s but can extended as far as 120km/s dependant on region.
- Giraffes gestation period is 15 months or between 453 – 464 days and their birthing interval between claves is 16 – 18 months.
- A Giraffe stands 3m tall at the end of 1 year, 4,5m by hour years and in excess of 5 meters after 7 years.
- Giraffe can live up to 25 years in the wild and 28 years on captivity.