Sivatherium Giganteum: Scientists Create 3D Replica of Morphologically Bizarre Ancient Giraffid

Most of us know the giraffe as quite an ungainly and massive animal ensconced amiably in zoos around the world. Most of us have seen footage of them thundering through the savannas of their native Africa. With spindly legs, a gentle nature, and famous spots, indeed they also claim their title on Earth as the tallest of all mammals. But there was once an ancient ancestor of the giraffe that while shorter, reigned much larger in mass, as a team from the Royal Veterinary College (RVC), University of London are learning. Putting their 3D scanners, software, and many fossils to work, they were able to create a fascinating digital replica of the ancient giraffid, known as Sivatherium giganteum.

Featuring a flattened countenance, horns, and strangely stubby legs, the prehistoric beast also had a surprisingly short neck–and seems to hail from one of those groups of fossils that when uncovered over two centuries ago had scientists stymied, scratching their heads over the strange legs and head shape.

It’s easy to see how early scientists may have not even put this creature into the same class with giraffes, rather assuming that it was an ancestor to the moose, rhino, or antelope. It walked the earth of India one hundred million years ago, chewing its cud just as its contemporary counterpart is so famous for doing, and was probably the largest animal of its type–known as a ruminant–one that chews the small balls of food sent back regularly from the rumen.

The researchers, Christopher Basu, Peter L. Falkingham, and John R. Hutchinson, discussed their findings in a recent paper, ‘The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation,’ published in Biology Letters by the Royal Society. In their paper, they explain that the giraffid, now long extinct, lived in the foothills of the Himalayas and was similar in size or a bit smaller than today’s African elephant.

“There has been no rigorous reconstruction of the entire skeleton of Sivatherium. Here, we present a three-dimensional composite skeletal reconstruction based upon the originally described material held at the Natural History Museum, London (NHMUK),” state the researchers in their paper.

“We then use this model to calculate a representative body mass estimate for this species, employing and comparing volumetric estimates with bivariate scaling estimates from skeletal measurements. In doing so, we provide an updated, modern scientific view of the shape and size of this long-neglected giraffid.”

The scientists used 26 fossils in combination with 1,000 photographs of other fossils to make the digital replica which they see as resulting in a true portrait of the ancient giraffid, referred to for many years as ‘morphologically bizarre.’ The true size of the animal may be an ongoing conversation however, as scientists think perhaps the animals could have grown even larger as some of fossils of leg bones and horns stand out as larger than the others. In creating their 3D digital re-creation of the beast, they made a foundation out of a regular giraffe’s torso, estimating that the Sivatherium probably had a body mass of 1,246 kilos, without the horns.

The scientists used only fossils that were that of mature specimens, and then created 3D models with Autodesk Maya software.

“We estimated the body mass of an adult Sivatherium using humeral circumference and convex hull volume. As in previous studies of large extinct animals, we expected there to be a discrepancy between volumetric and skeletal estimates,” stated the scientists in their paper. “We have also used thoracic circumference to make an estimate of body mass, as partial validation of the scaled-up Giraffa torso.”

Upon separating the skeleton into ‘functional segments,’ the scientists were able to employ the convex hull function offered by MeshLab to assign each segment a volume, as well as another one for the mandible, which was missing.

They concluded, for a variety of reasons, that the size/mass (1246 kg) they have assigned to the giraffid is probably on the low end, and with further study they could expand on “what may have been the largest ruminant mammal that has ever existed.” The researchers think the size issue could also be explored further in terms of sexual dimorphism and center of mass.

”Animals like Tyrannosaurus Rex get a lot of attention, but there are plenty of other bizarre fossil creatures that are surprisingly neglected in scientific research,” said Professor John Hutchinson of RVC. “It’s very satisfying to help bring Sivatherium the attention it deserves.”

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