Opposite Animal

The rules of the fun game Opposite Animal are as follows:

(1) The round begins with one person naming any animal.

(2) A second person then names the animal that is the opposite of that animal.

(3) Any participant may affirm or deny the merits of (2) as it relates to (1).

(4) If (2) is deemed not to be the opposite animal of (1), the game continues until the opposite animal is identified.

(5) Once the opposite animal is identified, return to (1).

Mohammed: "Hey guys, what's the opposite animal of a wooly mammoth?"
Kim: "Probably like an emperor penguin."
Fatema: "No, that can't be right, they both live in cold habitats."
Kim: "What about a pit viper?"
Fatema: "Hm, that sounds about right."
Mohammed: "Pit viper is correct."
Kim: "Well, what's the opposite animal of a hammerhead bat?"