Btw, a little detail that some non-locals might not be aware of regarding the San Diego Zoo and its sister-Wildlife-Park, is that the botanical splendor is nearly as wonderful as the animals... :-)
And because I'm throwing this post in my "photo tips" category, here's the tip: the best camera is the one with you. Use it!
ps. technical details: these are all SOOC. Android phone. Free FxCamera app. Polandroid setting. Square. Alternating between Vintage Film and Mono color settings.