According to the "Animal Face-Off's" narrator, in the elephant-rhino conflict brains had beat brawn. Personally, I didn't see the elephant use any excessive wits to defeat the rhino, or at least - need to use any wits to defeat the rhino. All the elephant had really needed was speed/maneuverability to avoid the rhino's charging attacks, and after that the elephant used his greater size and strength to overpower the smaller mammal. Thus, basically, brawn did beat brawn, and the brains were only marginally involved in this fight - i.e. if the rhino had been smart, it would not have messed with the elephant at all; it would have no reasons to, and plenty against.