Fossil marsupial predators of South America (Marsupialia, Borhyaenoidea): bite mechanics and palaeobiological implications

Borhyaenoids were marsupial predators that inhabited South America during the Cenozoic. They were very significant because no other mammals rivaled them as terrestrial hunters of large prey. Here we estimate the bite force of three species of borhyaenoids by two different methods to infer predatory behaviour in extinct taxa. One of the methods uses mainly the skull and only some simple measurements of the mandible; the other uses several measurements within the dentary. The results show that bite forces are very high in comparison to predators of the order Carnivora, a feature manifest by several other living and extinct marsupial predators. Differences in size, bite mechanics and special adaptations among the borhyaenoids suggest a very wide range of predatory behaviours that rival those represented in the extant families of the Order Carnivora.