Do guinea pigs need a night light to fall asleep?

Guinea pigs are native to South America and so can survive heat. But for tame guinea pigs it's best to make sure that you have an indoor cage away from direct sunlight, with a shady spot and somewhere dark to hide. If you have a run, don't put them out in the middle of the day because they will overheat. Try shady spots, putting a cover over the run or waiting for a breeze.