Advertisement Do tarantulas benefit from a day and night cycle? I don't mean putting a light on their enclosure. I mean being in a room with the curtains pulled back and natural sunlight falling in the room (not directly on the Ts emclosure) for approximately 12 hours or so. Would it be the same if they lived in a dark closet for ~24 hours a day? I know they don't have the best eyesight by any means, but that doesn't always mean the rest of the body can't sync with the cycle. Also, as far as I know, they don't really... "sleep" like mammals and other animals. Any scientific studies or research on the topic would be greatly appreciated! Opinions are, of course, welcome.