Dental caries in the fossil record: a window to the evolution of dietary plasticity in an extinct bear

Abstract

During the late Pleistocene of North America (≈36,000 to 10,000 years ago), saber-toothed cats, American lions, dire wolves, and coyotes competed for prey resources at Rancho La Brea (RLB). Despite the fact that the giant short-faced bear (Arctodus simus) was the largest land carnivoran present in the fauna, there is no evidence that it competed with these other carnivores for prey at the site. Here, for the first time, we report carious lesions preserved in specimens of A. simus, recovered from RLB. Our results suggest that the population of A. simus from RLB was more omnivorous than the highly carnivorous populations from the Northwest. This dietary variation may be a consequence of different competitive pressures.

Peer Review #2 of "First occurrence of the enigmatic peccaries Mylohyus elmorei and Prosthennops serus from the Appalachians: latest Hemphillian to Early Blancan of Gray Fossil Site, Tennessee (v0.1)"

“…Additionally, potential dental pathologies (e.g. caries such as those described by Andrews (1973), Coyler (1990), Figueirido et al (2017), and Wang et al (2017)) on the m1's of ETMNH 8046 further suggest a frugivorous or sugar-rich diet that would fit in with the current interpretation of the site being an oak-hickory forest.…”

Biogeographic problem-solving reveals the Late Pleistocene translocation of a short-faced bear to the California Channel Islands

“…The presence of dental caries suggests a high carbohydrate intake for Los Angeles-area populations 22 , and dental microwear attributes conflict with bone consumption associated with scavenging 23 . Carbon isotopes from inland California A. simus enamel indicate a signal of C3 vegetation, but there is no corroborating nitrogen value to distinguish animal protein consumption 50 .…”

“…The large sample size of A. simus cranial material from California (disproportionately from Rancho La Brea) has yielded dental-based inferences of diet that do not align with the meat-heavy diets of northern populations. The presence of dental caries suggests a high carbohydrate intake for Los Angeles-area populations 22 , and dental microwear attributes conflict with bone consumption associated with scavenging 23 . Carbon isotopes from inland California A. simus enamel indicate a signal of C3 vegetation, but there is no corroborating nitrogen value to distinguish animal protein consumption 50 .…”

“…Decades of debate have centered on the diet and life history of this enigmatic species; morphological diagnoses have included potential feeding ecologies as a hypercarnivore 14 , kleptoparasite 18 , omnivore 16 , and herbivore 19 . While stable isotopes from Beringian populations point to a carnivorous diet 18 , 20 , 21 , more indirect diet proxies such as dental caries 22 and dental microwear 23 dispute scavenging and high meat consumption in California populations. We provide the first collagen stable isotope values for this species in lower latitudes to address this gap in basic natural history knowledge of relevance to Late Quaternary extinctions and inform hypothetical mechanisms of dispersal to the CCI.…”

Late Pleistocene vertebrates from Three-Forks Cave, Adair County, Oklahoma Ozark Highland

“…The owl Bubo virginianus probably contributed to the accumulation of small vertebrate remains. Short-faced bears are thought to have been carnivorous-omnivorous and are implicated as scavengers of large mammal carcasses (Matheus, 1995(Matheus, , 2003Sorkin, 2006;Figueirido et al, 2010Figueirido et al, , 2017). Short-faced bears and dire wolves using the cave are additional potential sources of the remains of large mammals (horse, ground sloth), and possibly also of smaller mammals like the fox (Vulpini), brought in as prey remains or scavenged body parts.…”