The word comes from “mastodont,” which the Oxford English Dictionary tells us comes from

French mastodonte (Cuvier 1806, in Ann. du muséum d’hist. nat. de Paris8 270) < masto- + -odonte, with reference to the nipple-like tubercles present in pairs on the crowns of the molar teeth.

Perhaps those nipple-like objects came from Amazons,

< Latin Amazon, < Greek Ἀμαζών, -όνα; explained by the Greeks < ἀ priv. + μαζ-ός a breast (in connection with the fable that they destroyed the right breast so as not to interfere with the use of the bow), but probably pop. etym. of an unknown foreign word.

And of course they don’t call it Go Ogle for nothing.