Comparing grappling ability of extant Ursids

[Verdugo]

I posted these data some times ago on a different forum, perhaps I could copy them to here.

1. Differential scaling of the long bones in the terrestrial carnivora and other mammals
   
Humeri AP and ML Robustness:
American Black bear (i'll just throw ABB here for the sake of comparison): AP: 10.96%; ML: 9.71%; Total: 20.67%
Brown bear: AP: 11.76%; ML: 10.84%; Total: 22.6%
Polar bear: AP: 11.95%; ML: 9.83%; Total: 21.78%

In this study, Polar bear is more robust in AP while Brown bear is more robust in ML. Overall robustness of Brown bear is higher than that of Polar bear.

2. Scaling Patterns and Ecological Correlates of Postcranial Skeletal Robusticity in Canis and Ursus: Implications for Human Evolution
   
Humeri robustness (mix-sex):
American black bear: AP: 11.10%; ML: 9.65%; Total: 20.75%
Brown bear: AP: 10.84%; ML: 9.97%; Total: 20.81%
Polar bear: AP: 12.32%; ML: 9.77%; Total: 22.09%

Similar to the study above, Polar bear is more robust in AP while Brown bear is more robust in ML. Overall robustness of Polar bear is higher than Brown bear

3. Cursorial Adaptations in the Forelimb of the Giant Short-Faced Bear, Arctodus simus, Revealed by Traditional and 3D Landmark Morphometrics
   
Average humeri AP and ML robustness (measured by HAPW/HL and HMLW/HL respectively)

American black bear: AP: 11.50%; ML: 10.00%; Total: 21.5%
Brown bear: AP: 10.60%; ML: 9.80%; Total: 20.4%
Polar bear: AP: 12.50%; ML: 9.75%; Total: 22.25%

Similar conclusion to other 2 studies above, Polar bear is more robust in AP while Brown bear is more robust in ML. Overall robustness of Polar bear is higher than Brown bear

Overall, it does seem like Polar bears do have higher humeri AP robustness than Brown bears do while Brown bears have higher humeri ML robustness. High AP robustness would be more resistant to stresses from for-backward direction (AP direction) while high ML robustness would be more resistant to stresses from side to side (ML direction). Reply