Mastodons or Mastodonts (from Greek μαστός and οδούς, meaning "nipple tooth") are members of the extinct genus Mammut of the order Proboscidea and form the family Mammutidae; they resembled, but were distinct from, the woolly mammoth, which belongs to the family Elephantidae. Mastodons were browsers, while mammoths were grazers.
Mastodons are thought to have first appeared almost four million years ago. They were native to both Eurasia and North America but the Eurasian species Mammut borsoni died out approximately three million years ago - fossils having been found in England, Germany, the Netherlands, Romania and northern Greece. Mammut americanum disappeared from North America about 10,000 years ago, at the same time as most other Pleistocene megafauna. It is known from fossils found ranging from present-day Alaska and New England in the north, to Florida, southern California, and as far south as Honduras.