ELEPHANTS

African forest-dwelling elephants (Loxodonta cyclotis) are a separate species from those living in the African savanna (Loxodonta africana), researchers have shown.

Scientists have long debated whether African elephants belong to the same or different species. They look very different, with the savanna elephant weighing around 7 tonnes — roughly double the weight of the forest elephant. But studies had suggested they were the same species — DNA in mitochondria (the cell's energy factories) from African elephants found evidence of interbreeding between forest and savanna elephants around 500,000 years ago. Now a group of scientists have taken a deeper look at the African elephants' genetic ancestry.

The researchers sequenced the nuclear genomes of both types of African elephant, as well as that of the Asian elephant (Elephas maximus). They also extracted and sequenced DNA from the extinct woolly mammoth (Mammuthus primigenius) and mastodon (Mammut americanum) — ancient elephant ancestors.

By comparing all these genomes, the team found that the forest and savanna elephants diverged into separate species between 2.6 and 5.6 million years ago.

The study is published online in the journal Plos Biology.