Giraffes are found only in Africa. They are members of the genus Giraffa, and it was traditionally believed that only one species of Giraffe existed in the world, assigned the scientific name Giraffa camelopardalis. However, a number of genetic studies have indicated that the picture is far more complicated. They hint at the existence of multiple Giraffe species (that were till recently categorized as nine subspecies) across the continent. The nine are as follows:
- Angolan Giraffe (Giraffa giraffa angolensis)
- Kordofan Giraffe (Giraffa camelopardalis antiquorum)
- Masai Giraffe (Giraffa camelopardalis tippelskirchi)
- Nubian Giraffe (Giraffa camelopardalis camelopardalis)
- Rhodesian giraffe (Giraffa camelopardalis tippelskirchi)
- Rothschild’s Giraffe (Giraffa camelopardalis rothschildi)
- Somali Giraffe (Giraffa camelopardalis reticulata)
- South African Giraffe (Giraffa giraffa giraffa)
- West African Giraffe (Giraffa camelopardalis peralta)
Some studies split them into four distinct species, the Northern Giraffe (Giraffa camelopardalis), the Somali Giraffe (Giraffa reticulata), the Masai Giraffe (Giraffa tippelskirchi), and the Southern Giraffe (Giraffa giraffa). The only other genus of the Family Giraffidae to survive into the present is the Okapia which has just one species, the Okapi or Forest Giraffe (Okapia johnstoni). The latter is found in the tropical rainforests of Central Africa. The two genera evolved from a common ancestor nearly 12 million years ago.
Ancestral giraffids appeared around 25 million years ago in northern Africa and included the likes of Canthumeryx sirtensis (Early Miocene Libya). Soon giraffids had spread across Africa and Eurasia. They included the likes of Giraffokeryx punjabiensis (Late Miocene India) and Shansitherium fuguensis (Late Miocene China). By the Pliocene (5.3 – 2.5 million years ago), the group had split into two major branches, the robust-limbed Sivatheriinae and the slender-limbed Giraffinae. The latter contained the ancestors of the present-day Giraffes and Okapis.
The Sivatheriinae began diversifying in the Pliocene (5.3 – 2.5 million years ago) and Pleistocene (2,588,000 to 11,700 years ago) Epochs. It was from this branch of the Family Giraffidae that the gigantic Siva’s Beast arose. Like its close relatives, Bramatherium and Helladotherium, Sivatherium had a large body and stout limbs. The species Sivatherium giganteum ranged from Africa to South Asia. It had evolved during the Late Pliocene and survived as recently as 8,000 years ago (into the Holocene Epoch that began 11,700 years ago).
Named after the Hindu deity Shiva, its fossils were discovered from the foothills of the Himalayas (the Sivaliks). It was a most unusual-looking animal, more like an Okapi than a Giraffe. Standing 2.2 m at the shoulder and reaching a total height of 3.0 m, Sivatherium was a stocky creature that weighed around 1,250 kg. Some scientists believe that this figure is an underestimate, and does not take into account the impressive ossicones (horn-like skin-covered protuberances found in the Giraffidae) of the species.
Siva’s beast had a pair of massive ossicones and resembled in build the extant Moose (Alces alces of the Family Cervidae) of Eurasia and North America. While the Moose happens to be the largest species of deer on the planet (2.1 m at the shoulder, 700 kg in weight on average), the largest extant ruminant is the Masai Giraffe (reaching an average weight of 1,200 kg). Ruminants are cud-chewing ungulates of the evolutionary clade Ruminantiomorpha (that includes extant ungulate families like Tragulidae, Cervidae, Antilocapridae, Giraffidae, Moschidae and Bovidae).
The next largest extant ruminant is the Gaur (Bos gaurus) of South and Southeast Asia, reaching a weight of 1,000 kg on average. It is a member of the Family Bovidae. Sivatherium giganteum exceeded both on average, pushing the limits of ruminant anatomy. Ruminants use foregut fermentation taking place in their specially evolved four-chambered stomachs (comprising the rumen, reticulum, omasum and abomasum). This puts a limit on the amount of plant food they can ingest, and the speed and efficiency with which they can process the ingested food.
Another method, hindgut fermentation, used by the likes of Elephants and Rhinos (both unrelated to the Ruminantiomorpha) allows herbivores to grow to enormous sizes (for example, the African Elelphant, Loxodonta africana, and the White Rhino, Ceratotherium simum, attain weights of 6,000 kg and 2,300 kg on average). At 1,250 kg Siva’s Beast is considered by many to be the largest ruminant ever. Its short but well-muscled neck helped it carry its heavy ossicones and feed on the leaves, fruits, flowers and shoots of woodland trees.
The reasons for the disappearance of giraffids like Siva’s Beast are not known. However, some scientists hold the change in climate and vegetation responsible. As the world became increasingly arid, and grasslands expanded, the highly nutritious plant food required by gigantic giraffids to sustain their robust frames disappeared. Only the Giraffes of Africa, adapting themselves rapidly to a diet of Vachellia, Commiphora and Terminalia foliage survived. Anatomically modern human beings, with their deadly weapons and cooperative hunting skills could have played a part in their disappearance.
The only proof of their coexistence with Homo sapiens (apart from the usual fossilized remains) are paintings found in rock shelters of Central India. Here, in the valley of the Tapi River, on the Maharashtra-Madhya Pradesh (two large states of the region) border, prehistoric illustrations of Sivatherium were found in the Morshi Tehsil of Amaravati District, Maharashtra. They were discovered by a team under the leadership of a college principal, Mr. V T Ingole. Further investigation was carried out by the Archaeological Society of India, and the Rock Art Society of India. Also, discovered were paintings of Asian Elephants, Indian Rhinos and Bengal Tigers. South Asia must have harbored a truly stunning collection of megafauna back then, one to rival East Africa.
Image Attribution: The image above, sourced from Wikimedia Commons shows a painting of the extinct Sivatherium, taken from a card collection ‘Tiere der Urwelt’ (Animals of the Prehistoric World). It was the work of the German painter and art professor, Heinrich Harder (1858-1935) who specialized in landscape and natural history paintings and dates back to 1916.
- Fossil Focus: Giraffidae (Paleontology Online)
- ‘Largest Giraffe Relative Found’ (dated January 13, 2016, by Laura Geggel), Live Science
- The Extinct, Giant Giraffid Sivatherium giganteum: Skeletal Reconstruction and Body Mass Estimation (The Royal Society Publishing)
- Sivatherium (Prehistoric Wildlife)
- Rock Paintings Show Species that Roamed India (dated December 1, 2009, IANS), The New Indian Express