The living elephant species are contained within a single family, the Elephantidae, and are the sole remaining representatives of the mammalian order Proboscidea.
Both DNA and anatomical data indicate that the closest living relatives of elephants are the Sirenia
Recently, it has become clear that elephants and sirenians fall within a larger grouping, including hyraxes, tenrecs, golden moles, elephant shrews (whose long nose is, however, independently acquired from that of the elephant), and the aardvark. Together, this diverse assemblage of mammals has been named “Afrotheria”, since all are believed to have arisen in Africa from a common ancestor, 70 million or more years ago.
Three great branches of the elephant family can be recognized in the fossil record of the last 4 million years or so. These are:
The earliest fossil Loxodonta appears in deposits 7.3-5.4 million years ago (mya) in Kenya and Uganda. It subsequently divided into two apparently coexisting species, L. adaurora and L. exoptata. The living species, L. Africana, presumably derived from one of these forms, and initially coexisted with a further species, L. atlantica, with grazing-adapted dentition and small tusks. The relationships among all these forms are unclear, but recent genetic evidence has cast new light on the history of the African elephant. The ancestors of the living species almost certainly lived in the forests of central Africa. Between about 3.5mya and 2.5mya, drying of the climate led to the development of savanna-adapted populations in the south and east. This division led to the modern subspecies, L. africana cyclotis (the forest elephant) and L. africana africana (savanna elephant). L. a. cyclotis is today the more primitive of the subspecies; its skull is similar to that of L. adaurora.
Today, the bush or savanna elephant, L. a. africana, is distributed in eastern and southern Africa, while the forest elephant, L. a. cyclotis, occupies much of central and western Africa. The physical differences between them are very marked. In L. a. africana, the body size is larger and rangier, the ears are very large and triangular, the tusks are massive and curve outwards and forwards, and the back is distinctly saddle-shaped. In L. africana cyclotis, the body is distinctly smaller and more compact, the ears are smaller and rounded, the tusks are narrow, long, and downward-pointing, and the back is straighter.
These forms have been treated as subspecies of L. africana, but recent research has raised the possibility that they are separate species, L. africana and L. cyclotis. There are pronounced differences in skull and mandible anatomy, while DNA sequence studies found that forest elephants from central Africa were genetically quite distinct from those of the east and south African savannas, the genetic distance between the two groups being more than half as great as that between them and the Asian elephant. Finally, there are clear differences in habitat, feeding, social behaviour, and communication.
However, the precise geographical limits of the two forms have yet to be established. Moreover, despite the genetic differences, there is evidence of extensive hybridisation where the forms meet, and some populations (such as those in Ghana) are difficult to place in one group or the other. For these reasons, the IUCN’s African Elephant Specialist Group decided in 2002 to provisionally retain the designations at subspecies level, pending further research, and this policy will be followed here. Thus, the elephants are named L. africana africana for the savanna elephants of southern and eastern Africa and the West African sahel, and L. africana cyclotis for the forest elephants of central and West Africa. Records of the so-called pygmy elephant, L. pumilio, are almost certainly L. a. cyclotis.