In the evening I had the night safari booked. Apparently even Singaporeans do this. So I took the MTR, then the bus and arrived after driving about 90 minutes… so make sure to go there early. On the other hand, there were so many people – 5 minutes late – nobody would notice it.
Since my parents just were on safari in Africa, I was spoiled with pictures of wild animals. But if you have still some energy and probably little children, I would recommend to do this tour. On the way you can exit the tram and walk one or two paths on your own, which might be more interesting and fun (in my tram there were many Indians, who just did not manage to shut up and listen to the speaker).