Why do cats have vertical pupils?

Peering into the eyes of different animals, you'll see some extraordinarily shaped pupils. House cats, for one, are twilight hunters with vertically elongated pupils. Many grazing animals, like goats, have rectangular pupils. Other animals have crescent- or heart-shaped pupils. So, what's going on? Why are there so many different pupil shapes? Emma Bryce digs into the science of animal vision. [Directed by Bálint Gelley, CUB Animation Ltd, narrated by Alexandra Panzer, music by József Iszlai].