Do the hours of operation change later in the season? I'm planning on going in late October

Yes, call or check the website for current hours

If you go onto the zoo website they have someone to answer that question.

You have to leave the park by dusk, regardless of the time of year. Entry to the park closes 3 hours before dusk. The new aquarium closed today at 6, it changes to 5 at the end of September. Btw It's beautiful!