Animal life is less diversified than in other parts of South America because of the barrier to migration presented by the Andes. Indigenous mammals include llama, alpaca, vicuņa, guanaco, puma, Andean wolf, huemal, pudu, and the chinchilla. Birdlife is varied, but most of the larger South American types are absent. Aside from trout, which were introduced from North America, few freshwater fish inhabit Chilean streams and lakes.