There are 3 currently-recognised subspecies of Asian elephant, Elephas maximus:
The physical differences between them are a matter of degree and are expressed as gradual changes across the range:
In collaboration with colleagues in the UK, Israel and elsewhere, we have investigated the evolutionary origin of the Asian elephant through a comparison of fossils from northern India/Pakistan and the Middle East, many of them in the Museum collections.
Fossils from Bethlehem, excavated in the 1930s, are probably more than 3 million years old and may represent the earliest record of the mammoth/Asian elephant lineage out of Africa.
More recent remains, between 500-200,000 years old, still do not show fully-evolved Asian elephant features, suggesting that the modern species arose after that date.
Finally, in collaboration with colleagues in the UK, Denmark, Italy, and elsewhere, we have properly defined, for the first time since Linnaeus named the species in 1758, a type specimen (lectotype) for the Asian elephant Elephas maximus.
The elephants of north-east Borneo present an interesting case.
Genetically distinct from all other living populations, they may have been isolated there for hundreds of thousands of years, since Borneo was connected to the mainland during the ice ages.
However, there is circumstantial evidence that people imported them from Java a long time ago. Since elephants are extinct on Java, the Borneo population may represent the last surviving relict of the ‘Javanese’ subspecies.
Borneo elephants have been described as a separate subspecies, Elephas maximus borneensis. They are said to be pygmies, perhaps an example of ‘island dwarfing’.
A Natural History Museum-led expedition in 2008 investigated this claim by measuring the height of elephants in the field using a laser rangefinder technique.
Our results suggest that Borneo elephants are not significantly smaller than those of mainland south-east Asia. Our research on their status continues.
Lister, A.M., Dirks, W., Assaf, A., Chazan, M., Goldberg, P., Applbaum, Y.H., Greenbaum, N. & Horwitz, L.K. 2013. New fossil remains of Elephas from the southern Levant: Implications for the evolutionary history of the Asian elephant. Palaeogeography, Palaeoclimatology, Palaeoecology 386: 119–130.
Cappellini, E., Gentry, A., Palkopoulou, E., Ishida, Y., Cram, D., Roos, A.-M., Watson, M., Johansson, U.S., Fernholm, B., Agnelli, P., Barbagli, F., Littlewood, D.T.J., Kelstrup, C.D., Olsen, J.V., Lister, A.M., Roca, A.L., Dalén, L. & Gilbert, M.T.P. Resolution of the type material of the Asian elephant, Elephas maximus Linnaeus, 1758 (Proboscidea, Elephantidae). Zoological Journal of the Linnean Society170: 222-232.