Meeting Abstract
There has been limited biomechanical research on plantigrade species, despite the fact that this posture is ancestral and retained in many species. Within Carnivora, eleven of fourteen families are plantigrade or semi-plantigrade. Bears (family Ursidae) are a group of large, quadrupedal, plantigrade animals, which makes them unique. Our previous work has demonstrated some interesting characteristics of locomotion in grizzly bears. The aim of this study was to identify which, if any, of these characteristics were present in other bear species. Black bears live in similar habitats to grizzly bears and therefore may demonstrate some of the same locomotor patterns. We collected data from three captive adult male black bears. Preliminary results suggest that there are similarities between black bear and grizzly bear locomotion, but some of the unusual results from the grizzly bears are not present in the black bears. The vertical force traces were similar for both species, with a greater rate of force development in the hind limbs. Both species also used a transverse walk at slow speeds. The gait used at intermediate speeds differs between the two species; grizzly bears use a running walk, while the black bears appeared to use a pace. Grizzly bears produced relatively high lateral forces during locomotion, up to 13% of the vertical force. In the black bears this value is below 6%, which suggests they are not using their limbs for propulsion in the same way. Overall, our preliminary results suggest that the unusual aspects of grizzly bear locomotion are not shared by black bears, and therefore data need to be collected from more species to understand Ursidae biomechanics.
