The Miami Zoo is a great place for anyone who likes animals, walking, or just hanging out with the kids! This place is huge, and definitely has more to do than anyone can do in one day. Just for some kind of reference, take a look at the map I took a picture of and consider it takes 10-15 minutes to walk from the apex of one small curve to the next. It takes hours to walk through just one of the loops, and that's not considering standing still long enough to witness the animals living in their habitats.
I highly recommend checking this attraction out and blocking a couple days just for exploration. The zoo offers carts that anyone can rent and drive around in, but the exercise offered is a plus. Definitely wear tennis shoes or other comfortable footwear and clothes you feel comfortable sweating in, especially if it's going to be warmer than the mild 70s. And waterproof sunscreen is also a must, since there are mist stations everywhere, and you definitely want to use them for cooling off.
