Question for Peter

[tigerluver]

The former examples are of components, and like I said earlier, there are indeed differences in component pound for pound ability.

For birds, they may be more densely boned than bats of similar morphology. http://www.asknature.org/strategy/472817...S1hzxz3-iw
Bird bones are hollower, but the material itself denser, compensating for strength. Of course, birds are still quite weak compared to mammals. Most of your insectivores and herbivore species, parrots for example, are very weak. From personal experience, they can't lift more than 15% of their weight with their beak/neck. I'd guess birds of prey would be the exception though. 

The best predictor of strength is bone mineral density from my findings, it's just been ignored for the most part. Tiger bones are denser than other cats, and thus we see the odd bone width - in flesh diameters. From the skull bone densities I have gathered, bears outdo the big cats, and the tigers (especially island forms) outdo other big cats. In flesh robusticity seems to correlate well with skull bone density.  Reply