I went to the San Diego Zoo, the San Diego Safari Park, and Sea World all in the 6 days I was in San Diego. All of the parks were awesome, but the Safari Park was the best by far and shockingly far away from everything else.
* San Diego Zoo
I just visited this park last year, but it was a delight to come back. I was sad I wasn't able to see the red pandas or the regular pandas, but I rode the Sky Buckets and the tram that goes around the park to get a great view of all the different animals.
* Sea World
I know Sea World can be controversial because of documentaries like Blackfish, but I've never been. As a teacher, I received a free year pass plus some extra day passes to take people. It was a lot better than I was expecting. I watched their awesome Cirque de la Mer show which featured Cirque du Soleil style acrobatics and dancing in water. I also watched the Seal and Otter show, but I thought the otters weren't in it enough. We circulated the animal habitats and they were all adorable.
* San Diego Safari Park
This park is amazing and giant. It's in a very remote area, but the animals live as closely as possible as they would in the wild. I signed up to do the Raptor flight where we would interact with birds pf prey, but the 90+ degree weather was too dangerous for them. So we signed up for the Trike Safari and the Zip Lining. Both were very enjoyable.
The Trike Safari was about an hour trip on motorized tricycles (motorized trikes the size of bikes) in the Africa area where the grazing animals live: bongos, giraffes, rhinos, antelopes, camels, and various others. It was awesome to see the animals up close and to bike ride through these areas. The guides stopped every so often to allow trams to pass while informing us about the animals and answering any of our questions. The Safari Park has done so much to save endangered animals and now they are trying to save the Northern White Rhinos. Only 3 are left living, all past breeding age. Southern White Rhinos will eventually be surrogates for Northern White Rhino embryos in the coming years once they establish the method can work with their own species.
The Zip Lining was less informative, but crazy fun. First, we zipped 400 feet just to get used to it and then a short bus ride back to the African area for two thirds of a mile. We were instructed to stay quiet as rhinos are sensitive to noises. The rest of the park has the animals much closer to people than in conventional zoos. The most impressive animals I saw (not including the two events) were cheetahs, bats, lorikeets (who sat on my head as I fed them), and lions. I didn't get to spend as much time as I would have liked there, but I will definitely be returning next year for a longer stay.