Ever wonder if the lions roar more once the sun goes down? If you plan it right, you can roll out your sleeping bag and find out, in person — within a comfortably safe distance, of course.

Big zoos around the country increasingly offer sleepover nights for families — some in the summer,  and others year round—where you get VIP access to the exhibits and animals after the regular visitors have gone home for the evening.

Most sleepovers ask that you do rough it a bit—bring your own sleeping bag and pillow, and be prepared to sleep on the floor or ground—but in return you can get guided moonlight walks through the zoo, a campfire for roasting marshmallows, and behind-the-velvet-rope animal encounters. The bonus: rates are surprisingly reasonable. Here are eight zoos that throw great parties for families after dark: