Upload & Sell: On
Your choice is a matter of optimization among the factors that matter, such as budget, your ability to hand-hold a lens, how far you expect to be from the beasts, etc.
When I'm hunting for big game shots, I bring my 70-200 with extenders, and the 500/f/4 I. And a tripod with a gimbal mount. I've used the bare 70-200 for moose, and I've had times when even the 500 wasn't really enough to get bison.
If you're determined to hand-hold it, I certainly would recommend renting before buying any of the big lenses. I'm reasonably big, reasonably strong, and reasonably fit, but my 500/4 too much for me to hand hold for long. But there is no substitute for focal length when the beasties are a long way away (and some beasties you don't want to be so close).
My $.02; YMMV
I pray I did not give the impression I would be handholding 100% of the time... Give that 2% hand, 98% tripod with gimbal... When I go out alone I carry the 300 2.8 on the 7D and whatever rental lens I have on the 1DIV... I carry them to my blind and sit waiting on the game... Or I drive around until I spot game, try to anticipate their movement , and slip near them with one of the setups... I have successfully photoed deer, moose, and bear doing this... But now I am "Older" and am not going far from the car... Thank you for your advice...