Snakes that are active in daytime generally have round pupils. What about snakes that come out at night..What do they have?

Nocturnal snakes typically have vertical slit pupils (like cats), which helps them regulate light entry in dark conditions and enhances their night vision capabilities. Diurnal snakes generally have round pupils. The vertical pupil shape is an adaptation for low-light hunting. Snakes always have pupils, and horizontal pupils are found in some prey animals like goats, not snakes.