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The saber-toothed cat, Smilodon fatalis, and American lion, Panthera atrox, were among the largest terrestrial carnivores that lived during the Pleistocene, going extinct along with other megafauna ∼12,000 years ago. Previous work suggests that times were difficult at La Brea (California) during the late Pleistocene, as nearly all carnivores have greater incidences of tooth breakage (used to infer greater carcass utilization) compared to today. As Dental Microwear Texture Analysis (DMTA) can differentiate between levels of bone consumption in extant carnivores, we use DMTA to clarify the dietary niches of extinct carnivorans from La Brea. Specifically, we test the hypothesis that times were tough at La Brea with carnivorous taxa utilizing more of the carcasses. Our results show no evidence of bone crushing by P. atrox, with DMTA attributes most similar to the extant cheetah, Acinonyx jubatus, which actively avoids bone. In contrast, S. fatalis has DMTA attributes most similar to the African lion Panthera leo, implying that S. fatalis did not avoid bone to the extent previously suggested by SEM microwear data. DMTA characters most indicative of bone consumption (i.e., complexity and textural fill volume) suggest that carcass utilization by the extinct carnivorans was not necessarily more complete during the Pleistocene at La Brea; thus, times may not have been “tougher” than the present. Additionally, minor to no significant differences in DMTA attributes from older (∼30–35 Ka) to younger (∼11.5 Ka) deposits offer little evidence that declining prey resources were a primary cause of extinction for these large cats.

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The power stroke of mastication has been traditionally divided into two parts, one which precedes centric occlusion, and the other which follows it --"Phase I" and "Phase II" respectively. Recent studies of primate mastication have called into question the role of "Phase II" in food processing, as they have found little muscle activity or accompanying bone strain following centric occlusion. That said, many researchers today look to "Phase II" facets to relate diet to patterns of dental microwear. This suggests the need to reevaluate microwear patterns on "Phase I" facets. Here we use texture analysis to compare and contrast microwear on facets representing both phases in three primate species with differing diets (Alouatta palliata, Cebus apella, and Lophocebus albigena).Results reaffirm that microwear patterns on "Phase II" facets better distinguish taxa by diet than do those on "Phase I" facets. Further, differences in microwear textures between facet types for a given taxon may themselves reflect diet.Some possible explanations for differences in microwear textures between facet types are proposed.