Implications of the dental eruption sequence in Barbourofelis (Carnivora, Nimravidae) for the function of upper canines and the duration of parental care in sabretoothed carnivores

The eruption of the large deciduous upper canines in the nimravid sabretooth cat Barbourofelis was delayed until after the individual was eating meat. This inference is based primarily on the eruption sequence and dental wear displayed by seven specimens referred to this genus. It indicates that the sabres were not required for feeding and suggests that these teeth were primarily killing devices. The deciduous upper canines in Barbourofelis and the permanent canines in large felids probably erupted at similar stages of dental ontogeny. If the potential for independence from adults occurs with the eruption of canines that were large enough to serve as killing devices, the delayed eruption of the deciduous sabres in nimravids did not necessitate any significant extension to the long period of parental care that is typical of the extant Carnivora. Summary The eruption sequence of, and patterns of wear to, the dentition of Barbourofelis demonstrate that juveniles were processing meat before the eruption of the deciduous sabres and thus the upper canines were not necessary for feeding. This supports the view that the sabres were preferentially killing devices; any use of the sabres in dismemberment of the carcass by adults was probably secondary. The transfer of these inferences to felid sabretooths such as Smilodon may be unwise; however, arguments that Smilodon's sabres were inefficient slicing devices (Simpson, 1941), and the patterns of wear on its incisors and cheekteeth (Miller, 1969; Akersten, 1985), suggest that a similar scenario is likely. The marked modifications to the morphology and eruption sequence of the dentition in Barbourofelis may not have resulted in any significant increase in the length of parental care.