That is the funnest post I've read here in years.As others have said: once one is used to their anatomy, it isn't difficult to be effortless, even graceful.
Also, as I'm sure many people with female pelvises can tell you: wider hips don't necessarily mean wider step. It isn't difficult to do, at all. That's how supermodels walk the runway, and they do it in heels. I'm not an apelike cryptid, nor do I have notably wide hips, but I often walk with my feet at center line. It's a style choice.
The difference between when I do it and when Patty the Bigfoot does it is that my hips sway when I walk with my feet centered. That's the whole reason why some women do it: it looks 'sexy'. Mechanically, the act of getting my feet at center while walking causes my hips to tilt and sway as the weight is shifted from leg to leg. Patty's do not. If they did, she'd be walking like a sexy cartoon character. Patty walks like a linebacker, not Jessica Rabbit.
I actually find this fact to be proof that there is a man (with narrower hips) in a suit with built-out hips: he walks normally, with his feet at characteristic distance apart, and they appear close together because he's got an ape suit on that adds the appearance of a bigger hips and butt. If the bigfoot was real, there is no way that it would be naturally walking with its feet at center without a very distinct hip sway.