Antler Guys are official Maxis creatures present in the final game. They are reptiles with birdlike beaks, and interestingly, antlers. They have four legs, but only one set of hips, their legs branching out one joint down. It would appear that they were, at one time, bipedal, but at some point, the one pair of legs split into two, perhaps from a growth on the back of the legs.
Antler Guys are adept at charging, and if provoked, they will do so. Their charge will cause great damage to the target, and daze it while the Antler Guy is free to bite until the foe collapses. Though if that doesn't work they are very fast, and can outrun most creatures.
But Antler Guys are also social creatures. They have been known to sing and dance fairly well, and it takes some effort to impress them, unless charming or posing.