While studying buffalo and wildebeest in Serengeti, Dr. Sinclair would watch these animals at night with "night vision" goggles. On starless nights, the ground appeared black and the sky a greenish color on the screen. Animals appeared as either black or grey shapes silhouetted against the sky. Strangely, every now and then, a wildebeest would just disappear and then re-appear a few seconds later. After watching this occur a few times, a powerful spotlight was brought into play. Standing among the wildebeest were a group of zebra, invisible on the goggles. Since then, technology has improved, but the zebra remain invisible at night.
There must be something about the stripes, whether they reflect light differently in the longer wavelengths, which are sensed by our eyes at night, or the pattern confuses our eyes in the dim light. "It makes sense you see", Dr. Sinclair said, "zebras don't care what they look like during the day, their predators, lions, only hunt at night ... that is the time that zebras have to be camouflaged."