SGU Friday Quiz extra info (spoilers)
Camels do indeed have three eyelids. Specifically they have a nictitating membrane, a transparent eyelid that allows (some) vision whilst still protecting the eye.
A social network for lovers of science, rational thinkers and skeptics. Darwin portrait by David Revoy under CC license (https://www.davidrevoy.com/article145/portrait-of-charles-darwin)