The last time I went to the Changsha Zoo was in 2004 and it was horrible. Small dirty cages with unhealthy animals. The big cats were all skin and bones, pacing back and forth. Most animals had huge sores and their bodies looked half-dead. Their eyes... fully dead.
I went with trepidation to the new zoo (a few years old now) they call an ecological zoo and it was really quite nice. It's spacious and the animals look really good. Healthy and often playing. I used to raise snakes for the pet trade and I was pleasantly surprised to see how good their reptile housing was. Quality enclosures and equipment and very clean.
They had buses through the safari area and carts to take you to certain points in the walking area. Everything, save the reptile and panda housing was open air. The monkeys were not caged but on islands with moats they couldn't cross. The lemur island was accessible and you could play with them.
All signs had English translations, although the preferred dialect was Chinglish.
If it wasn't for the animals visiting (people throwing water bottles at the animals to get their attention or just to be the really super cool guy that hits the tiger, banging on glass, tossing garbage everywhere except the trash containers) it would have been almost perfect as far as zoos go.
Your photos always amaze me. 
Thank you.