On reconstructing Giraffa sivalensis , an extinct giraffid from the Siwalik Hills, India

An extinct giraffe's size depends on which bone you trust. Giraffa sivalensis was named from fossils in India's Siwalik Hills, but no complete skeleton establishes its proportions. A single neck vertebra anchors the species' identity, while other bones assigned to it suggest a rather different-sized animal.

S. J. van Sittert and Graham Mitchell re-examined that vertebra and four limb-bone fragments in London's Natural History Museum, alongside published tooth measurements. They used relationships between bone dimensions and body size in living giraffes to reconstruct the extinct animal, checking their approach against okapi skeletons. They also reassessed which position the neck bone occupied, identifying it as the third vertebra rather than the fifth.

The neck-based reconstruction suggested a mature individual of roughly 400 kilograms, with a neck about 1.5 metres long. Estimates from some limb fossils were substantially larger. The difference could reflect males and females of different sizes, incorrect assignment of fossils to the same species, or body proportions unlike those of living giraffes. Because the bones were not found as one connected skeleton, those possibilities cannot be resolved here. The useful result is a bounded reconstruction of one ancient giraffe, and a demonstration of how much a missing skeleton leaves uncertain.