They decided to use a program called "enrichment" on them, which basically consists on adding new things to their environment every now and then. This is meant to make them curious and want to wander around to explore the newly added elements, thus being stimulated to stay active and moving for people's amusement. Of course, it is a clever way to keep them up, but I wonder if it is really any good for their sleeping schedule. Given the fact that they are used to sleeping during the day and hunting during the night, how can they deal with their feeding times, then?
While this issue is also present, to a lesser extent, with other animals, it is easier to deal with than with tigers. One thing they do a lot is camouflage feeders in open areas to attract animals to them.