Nocturnal animals in zoo exhibits face welfare challenges when housed in day-lit conditions, requiring reversed light cycles or specialised exhibit design to support natural behaviour.
Nocturnal animal welfare in zoos requires recognition that standard daylight exhibit conditions fundamentally conflict with these animals' biology. Bright daytime lighting suppresses melatonin, disrupts circadian rhythms, and causes the equivalent of chronic jetlag in animals whose physiology is tuned to nocturnal activity. Reversed light cycle exhibits — in which red lighting simulates dim moonlight during visitor hours, allowing natural nocturnal activity — represent the welfare-appropriate solution. The welfare cost of keeping nocturnal animals in normal lighting conditions is chronic physiological stress and suppression of natural behaviour patterns that accumulates over the entire captive lifetime.