How do animals attain enlightenment? The Wikipedia article on animals in Buddhism states that animals have Buddha nature, and therefore have potential for enlightenment. I do not dispute this as I sit here petting my cat, but wonder - what are the actual mechanics of how they might go about this? For humans, the path is laid out for us in the teachings of the Buddha. But how can an animal achieve the same final goal?
In short they get reborn as a human being sometime in the future and practice. 

You could help by reading some dhamma(suttas) to your cat if you wish.

There is a precedence in a sutta where a frog was listening to a Buddha's discourse and got killed because someone accidentally impaled it with a walking stick. It was then reborn as a deva.