This is neat, did you create this? I could see a similar graph for other major collections in close proximity (ie Woodland Park Zoo compared to Point Defiance Zoo, Brookfield Zoo compared to Lincoln Park Zoo, Dallas Zoo compared to Fort Worth Zoo, San Diego Zoo compared to San Diego Wild Animal Park, Franklin Park Zoo compared to Stone Zoo etc.)
Though there would be likely no overlap, I might add Arizona Sonora Desert Museum compared to Reid Park Zoo.
