Mammoth construction of the Great Pyramid of ancient Egypt. The earliest known proboscideans, the clade that contains the elephants, existed about 55 million years ago around the Tethys Sea area. The closest relatives of the Proboscidea are the sirenians and the hyraxes. The family Elephantidae is known to have existed six million years ago in Africa, and includes the living elephants and the mammoths. Among many now extinct clades, the mastodon is only a distant relative of the mammoths, and part of the separate Mammutidae family, which diverged 25 million years before the mammoths evolved. The following cladogram shows the placement
Mastodon herbaceous vegetation, implying a mixed browsing and grazing diet, with evidence provided by studies of isotopic bone chemistry indicating a seasonal preference for browsing. Study of mastodon teeth microwear patterns indicates that mastodons could adjust their diet according to the ecosystem, with regionally specific feeding patterns corresponding to boreal forest versus cypress swamps, while a population at a given location was sometimes able to maintain its dietary niche through changes in climate and browse species availability. The range of most species of "Mammut" is unknown as their occurrences are restricted to few localities, the exception being the American mastodon ("M.