African forest elephant
Scientists used to think both animals were subspecies of a single African elephant. However, a study published in 2010 found that each elephant belonged to its own species and that the lineages diverged between 2.5 and 5 million years ago, or about as long ago as humans split off from chimpanzees.
(Both African elephant species are now endangered, one critically.)
African forest elephants are about half the size of their closest cousins, and their tusks are straighter and point downwards compared to the outward curving tusks of savanna elephants. Males, or bulls, can have tusks that nearly scrape across the ground. Forest elephant ears are also more oval-shaped, as opposed to the