You can all thank whiskey for this thread resurrection.
After a discussion that started with wanting to create a hunting show where a man has to hunt deer using only his bare hands, I decided to rehash this thought experiment last night with our friends.
This scenario depends on the starting position of your team versus everyone else. If you're in the middle of an arena surrounded by everyone else, you're just hosed. If every team starts one the edge with their backs against a wall, you at least have a chance.
Also, the distance and sight lines between you and the hunter are pretty important. Too far away and the hunter will pick you off within seconds. If they are closer, you might be able to hide behind buffalo or gorillas long enough to eliminate the hunter.
I was on team rats/hunter for a long time but I've come around to either buffalo/gorillas or hunter/buffalo.
Buffalo/gorilla: The first order of business would be to stampede charge the hunter and take him/her out. You'd have to sprint behind an aggressive buffalo charge winged by gorillas. You'd likely lose a few of your team, but you must remove the long range threat. For this strategy to ultimately work, you'd have to keep attacking to avoid getting surrounded, but the gorillas could help hold off enemies while the buffalo rested for another charge.
Or...
Buffalo/hunter: similar to the above example, you aggressively charge and trample other animals while running behind or possibly riding the buffalo. The hunter would play the same role as the gorillas did.