Eevee is based on a mix of different animals, including rabbits, cats, and foxes. Some sources suggest that Eevee shares most traits with the fennec fox, while others mention that it is based on dogs, cats, and rabbits. One source even suggests that Eevee is based on a "cabbit," which is a mix between a cat and a rabbit. Overall, it seems that Eevees design is a combination of various small, cute, and furry animals, rather than being based on a specific real-life creature.