That particular shot you were asking about sounds like it was shot with a steadicam or a pole cam (small camera on a long pole). Lots of wildlife filmmaking these days is with habituated animals or a combination of natural history and staged shots. It's also common to reverse engineer a shot from a "money shot" to the events that might have led up to it. Heck, even Cousteau staged shots. The general standard is "if it could happen in a natural setting" for staging a shot. Natural history film budgets have shrunk so much that more is staged these days. Also, while we are well aware that certain types of activities take place (finding a prey animal in another animals stomach), the odds of actually filming it live may be pretty slim. It's even tougher with underwater subjects. I stage things all the time, things like sea urchins breeding, feeding behavior, unusual types of things like time-lapse and territorial fighting. These are common events but does it happen when you happen to be in a tidepool with a housed movie camera and a couple of thousand watts of lighting? Hate to bust any balloons but most of us are on a schedule and a budget and it's a business as much as anything else is...