Elephants, giraffes, zebras and most ungulates are not strictly nocturnal nor diurnal. Like what Arizona Docent mentioned, these animals sleep for short durations throughout the entire day.
In any case, the Night Safari has one of the shortest operating hours of any zoo in the world - 5 hours every day (7pm till midnight, after which the lights are turned off). For the rest of the 19 hours, the animals are free from visitors staring at them and can rest as they wish.
hi if you are really serious in shooting animals at the nocturnal house or zoo, you need a DSLR with high iso, a good tele lens with a wide aperture, a sturdy tripod and a cable shutter release. even with these it is still difficult to photograph the animal esp when they are really active. i had previous posted shots i had taken of the animals at the night safari you can take a look
hi if you are really serious in shooting animals at the nocturnal house or zoo, you need a DSLR with high iso, a good tele lens with a wide aperture, a sturdy tripod and a cable shutter release. even with these it is still difficult to photograph the animal esp when they are really active. i had previous posted shots i had taken of the animals at the night safari you can take a look