I suspect the major contributing factor is muscle/fat ratio. OK so the Sumo (and he was quite small compared with some of those chunks) weighed 363lbs (that's about 25st or 164kg for us Yookers) but how much of it was muscle and how much was just fat? I've seen muscle-men and they don't look like an inflatable chair.

Orangs spend most of their time moving around, swinging through libraries, sorry, jungles and trees, and as far as I'm aware, haven't succumbed to stuff from McDonalds yet.

In a bet between any human and an orang, my money is on the little orange hairy, four handed one...

LTS