Conclusions

Dental microwear studies are valuable in qualitatively addressing patterns of food use in both extinct and extant vertebrates. This study has examined dental microwear patterns on the teeth of Campanian/Maastrichtian hadrosaurs from northern Alaska to western Texas. The results of the examination have shown similar patterns of tooth wear independent of geographic location, suggesting that hadrosaurs all along western North America were consuming food items with similar hardness.

The dominant food is considered to be conifers, although it is unlikely that conifers constituted the entire diet of high latitude hadrosaurs given the constraints imposed by a highly seasonal annual cycle, that cycle largely defined by variation in light regime. Further, given the similarity of food items consumed along such a large latitudinal gradient, combined with the deciduous nature of the food items in Alaska, it seems likely that northern hadrosaurs reduced their metabolic rates during the winter months, in a manner similar to many modern terrestrial arctic vertebrates. This reduction in metabolic rate during the winter months may have been facilitated if these animals were large-bodied ectotherms rather than endotherms.