How close are living elephants to the woolly mammoth?
Based on fossil evidence and studies of DNA and protein sequences, it is estimated that mammoths diverged from Indian elephants about 7 million years ago, not long after they diverged from African elephants. The next closest mammoth relatives that are well known today are the extinct mastodons, which diverged from mammoths and living elephants over 20 million years ago. After that, the closest living species are the hyrax and dugong, which diverged from elephants and mammoths perhaps 60 million years ago, almost back to the age of the dinosaurs.
Panel a of the following figure shows the relationships among mammoths and the living elephant species, with African elephants consisting of two species (savanna and forest elephants) and showing the two groups of mammoths (corresponding to samples M4 and M25, as discussed elsewhere on this website). The time scale (shown in millions of years) is similar to that for humans and their closest relatives (panel b). However, the mammoth and elephant genome sequences are more similar (99.4% identity) than are human and chimpanzee (98.8%) because the DNA in elephant species is changing more slowly, perhaps because of their lower metabolic rate. At the level of protein sequences, mammoths and elephants are even more similar: we estimate 99.78% amino-acid identity.