No this is not some 'Darwinesque' type experiment, but rather the colorful language used in variations of the backgammon game, whether played on, or off line. For Money Play the following example which we shall name 'animal Game' is as follows. Player One doubles, and player Two believing they are in a better position holds the dice, it is then up to him to decide to turn the dice an extra notch keeping the dice on his own side.
Follow this game, if Player one makes throws a double to 2, Player Two may, instead of taking the double and holding a 2 dice, say... (Wait for it) 'BEAVER' then turns the dice an extra notch to number 4, and continues the game holding a 4 dice.
Now if Player one thinks he has made a bad move meaning his BEAVER was a mistake, and then he can call 'RACCOON 'thereby moving the dice one more notch to 8 for example). The dice now remains with Player Two as he could if he like turn the turn the dice a further notch, saying RHINO,OR ANTEATER OR RABBIT, or any particular creature he prefers whatever term is declared is purely a matter of conjecture. The game play goes on and on and until someone takes out a rifle (metaphorically and shoots the animals) or loses the game.
Remember Beavers and what other animals end up on the board is not allowed in matches, I wonder why?