Almost a majority, perhaps a majority of mammals are nocturnal. Most mammals see the world in shades of gray. The World of Darkness at the Bronx Zoo came about as the vision of the mammal curator, in those days, Joseph Davis. And Joe felt that he could exhibit colorblind animals as virtually all nocturnal animals are by using red light. The story is developed beyond red light, but his concept was a very thoughtful one because most nocturnal animals are particularly red colorblind. So he thought he could use, really, a very intense red light and the animals would be comfortable and feel they were in the dark, and by lighting their exhibits brightly during the night, he could reverse their cycles. It worked. So he took the old small mammal house, which was not a good building.
