I spent a day watching fox videos on you tube and realized foxes have vertical slit pupils! I looked up what animals have vertical slits and found it was cats, foxes, geckos, alligators, vipers and some species of birds. They are predators which are low to the ground and the vertical slits offer advantages. I had heard foxes had canine hardware and feline software, but they have some hardware mods, too - the vertical slit pupils, and some have retractable claws! http://www.sci-news.com/biology/science-pupils-shape-eyes-animals-03112.html