This may be the pettiest bug one can think of, but I figured it was a bug none-the-less so I may as well post it. The bug is I noticed when I zoomed in on my city that, even though I had not researched Domestication yet, there was an inordinate amount of horses running around near the Farmer's Quarter- more horses than people even. Now either a herd of wild horses decided to occupy Babylon, or the graphical effects for an Ancient city doesn't check if Domestication is researched before spawning domesticated animals.