A large sample (N=76) of Pleistocene mastodon (Mammut americanum) teeth from a variety of localities in Florida were analyzed for dental enamel microwear features via low-magnification stereomicroscopy. Second upper and lower molars were used for dental dietary reconstruction purposes to allow comparison of results to an extensive molar microwear database comprised of extant taxa with well-studied diets. Deciduous premolars and permanent molars were tested for consistency of enamel scar patterns. We used both Kruskal–Wallis and Mann–Whitney tests to test for differences across the tooth row in: (1) average pit frequency, (2) average scratch frequency, (3) scratch textural properties, and presence or absence of (4) gouges, (5) large pits, and (6) cross scratches. Of these variables, only the gouges showed significant between-tooth differences at p
Stereoscopic microwear results were compared to an extant herbivore microwear trophic triangle representing average scratch and pit morphospaces for extant taxa, including graminivores, folivores, and frugivores. Enamel scar patterns for M. americanum for six microwear variables are consistent with a browsing diet but apparently one unlike that of typical extant browsing forms. Evidence for extensive bark consumption and some fruit consumption is presented. Cluster analysis reveals a clear segregation ofM. americanum from typical extant browsing forms, from grazing or mixed feeding forms, and from extant African and Indian elephants. Euclidean distance comparisons reveal a dietary profile most similar to that of the extantDiceros bicornis (black rhino), a well-known browser with a prehensile lip that is used for gathering twigs into its mouth. Our results are consistent with reports for Florida mastodons showing a preponderance of twigs such asTaxodium (bald cypress) in preserved digesta.