I thought this was interesting, although not surprising when you stop to think.

http://www.scientificamerican.com/podcast/episode.cfm?id=bigger-animals-keep-a-stiff-lower-f-10-03-01

"Big cats or wolves seem like scaled-up versions of the tabby or terrier sleeping on your sofa. But the proportions do subtly change as animals get larger. For one thing, big animals’ feet are smaller relative to their bodies than are smaller beasts’. But they compensate with physics, according to new research in the Journal of the Royal Society Interface. [see: http://bit.ly/cDdbUx]

When we think about animal locomotion…whether it’s walking, running, or just standing around…we usually focus on the bones and muscles in the legs and feet. But for four-legged critters, it’s the footpads that ultimately support the animal’s weight. So scientists [Kai-Jung Chi, National Chung-Hsing University, Republic of China (Taiwan) and V. Louise Roth, Duke University] decided to take a closer look at these “natural shoes” in different-sized carnivores, including dogs, cats, wolves, leopards and hyenas.

And they found that the relatively smaller footpads of, say, leopards are much stiffer than those of little bitty kitties. Apparently so that the big cats’ feet can handle the stress of the greater body weight. If a tiger’s paws were as soft as a house cat’s, he’d need hippo-sized feet to stand.

It’s said that the bigger they are, the harder they fall. But now we know that the bigger they are, the harder their feet."

—Karen Hopkin