My first safari i rented a 200-400 in Johannesburg and took that to a game reserve near Kruger national park. After that trip i flew home, ordered a 200-400mm from B&H and flew back to Africa to go on this very trip.

I have/had a 70-200 but in Africa that is almost a wide angle.

My last trip i shot with 3 bodies.
D3 + 200-400mm
D3 + 14-24mm
D300s + 70-200mm (because this one vignettes so badly on a full frame body)

In the future i hope to retire the 200-400mm and replace with a 300mm fixed and a 600mm fixed. A fixed super tele is so much sharper than a zoom. I am sure though once i do this i'll miss the flexibility of the 200-400mm.