Biologists have long recognized morphological differences between Africa's forest-dwelling elephants and those that inhabit the savanna. But they have always considered the two types to be members of the same threatened species. The results of a genetic study described today in the journal Science, however, indicate that the elephants form distinct groups and thus merit recognition as separate species. The new findings could impact Africas elephant conservation efforts.

Stephen J. OBrien of the National Cancer Institute and his colleagues analyzed DNA obtained from 195 free-ranging elephants from across Africa, as well as DNA from seven Asian elephants (which were already considered a separate species). Focusing on sequences from four nuclear genes, the team found differences between forest and savanna elephants amounting to more than half that seen between African and Asian elephants. They also detected very little evidence of interbreeding between the two African types. On that basis, the researchers propose reassigning the forest elephants from the species Loxodonta africana to Loxodonta cyclotis.

Distinguishing the forest and savanna elephants in this way could have important implications for conservation management of the two groups. Forest elephants, which are concentrated in politically unstable countries, face particularly intense pressure from human activities. "Given the rapid depletion of both forest and savanna elephant numbers in the past century and the ongoing destruction of their habitats, the conservation implications of recognition and species-level management of these distinct taxa are considerable," the authors write