Some of the exhibits used to be open, but they changed that because having guests in the exhibits at night was messing with the animals' well-being.

I also know that they stopped using a certain type of light and instead did another type of light (not sure of which specific lights). Again, due to the previous ones causing problems for the animals' well-being.

The Zoo is trying to basically do what they can to make it enjoyable without compromising their primary goal: preserving the well-being of their animals.

It might be a bit disappointing for visitors, but I'm glad they're prioritizing the zoo animals, personally.