Nonsense, everybody knows that nonhuman non-pokemon animals are just an urban legend, like the Indian Elephant.
In the pokeverse is a game called Animals, and in gen 3 one of the gym leader uses two Indian Elephants as part of her team, along with the Imperial Mammoth as her signature mon. Unfortunately they are weak to lightning-based attacks.
Also, the Gallus is an extremely common animal found early in the game, and is very weak and useless. However, should one train it until level 40, it will evolve into the fearsome Gastornis, capable of learning devastating moves such as Hi Jump Kick and Sky Attack (God Bird in the original transcript).