Evolution and taxonomy of living elephants
Genetic research has raised the possibility that the two classic forms of elephant in Africa are separate species rather than subspecies of Loxodonta africana. Museum research has uncovered populations with a mosaic of features.
There are two forms of African elephant, with different distributions and very marked physical differences:
- The bush or savanna elephant is distributed in eastern and southern Africa. It has a large and rangy body, very large and triangular ears, massive tusks which curve outwards and forwards and a distinctly saddle-shaped back.
- The forest elephant occupies much of central and western Africa. It has a distinctly smaller, more compact body, smaller, rounded ears, narrow, long and downward-pointing tusks and a straighter back.
Subspecies or species?
In the past, the two forms have been treated as subspecies of Loxodonta africana:
- L. a. africana (African bush elephant)
- L. a. cyclotis (African forest elephant)
Recent genetic research has raised the possibility that they are separate species:
- L. africana
- L. cyclotis
This question is important because it helps shape the conservation policies of international organisations like:
- The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)
- International Union for Conservation of Nature (IUCN), which publishes the IUCN Red List of Threatened Species
- Transition zone elephants
A 2004 expedition to Ghana studied a population of elephants in the transition zone between the classic savannah and forest forms. We found a mosaic of features, including body size as large as savannah elephants, tusk and head shape like forest elephants and intermediate ear shape.
- Ear shape
A further study investigated ear shape by comparing a series of populations across Africa. Although the difference between some classic forest and savannah populations is clear, others show a range of forms, making them difficult to classify as one or the other.
These studies indicate that both genetic and anatomical data are needed to correctly classify all populations of elephants. We hypothesise that ‘intermediate’-looking animals are a result of hybridisation, or the adaptation of some populations of forest origin to a more open environment in West Africa.
Our study has focussed on historical populations of Asian elephants that lived in the Near East, far to the west of the species’ current range in the Indian subcontinent and south-east Asia.
We studied skulls and skeletons of elephant excavated in an area of south-east Turkey, and dated them by radiocarbon to the Bronze Age, around 1500 BC. DNA analysis of the bones (the first ancient DNA from this species) showed them not to be genetically distinct from living Asian elephants, even though they had previously been named as a distinct subspecies.
The bones show no trace of human activity, so we consider this to be a wild-living population, rather than one brought from the East for domestic use, although this is a subject of debate.
Further back in time, remains of Elephas hysudricus, the species considered ancestral to the living species Elephas maximus, have been identified from sites in Jordan and Israel, some of them as late as 300,000 years ago (half the age of the latest fossils from India), suggesting the origin of the living species was quite recent.
Flink, L.G., Albayrak, E.L. & Lister, A.M. 2018.
Genetic insight into an extinct population of Asian elephants (Elephas maximus) in the Near East.
Open Quaternary 4: 1-9.
Cappellini E, Gentry A, Palkopoulou E, Ishida Y, Cram D, Roos A-M, Watson M, Johansson US, Fernholm B, Agnelli P, Barbagli F, Littlewood DTJ, Kelstrup CD, Olsen JV, Lister AM, Roca AL, Dalén L, Gilbert MTP. 2014.
Resolution of the type material of the Asian elephant, Elephas maximus Linnaeus, 1758 (Proboscidea, Elephantidae).
Zoological Journal of the Linnean Society 170: 222-232.
Lister AM, Dirks W, Assaf A, Chazan M, Goldberg P, Applbaum YH, Greenbaum N, Horwitz LK. 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.
Albayrak E, Lister AM, 2012.
Dental remains of fossil elephants from Turkey.
Quaternary International 276: 198-211.