Just out of curiosity, do neighboring zoos in large cities compete with each other? It seems to me that even in cities (or metro areas) with more than one zoo, you might see similar collections. For example, Denver and Cheyenne Mountain both have some of the same charismatic species. Is the rest of their collection different enough that the two zoos don't compete? What about Lincoln Park and Brookfield? Are they far enough apart that people usually just choose to visit one or the other or do they have some of the same charismatic species but then have some different species they specialize in? Sorry I couldn't think of another way to explain this. Also, have there been cases in cities with more than one zoo where one actually put another one "out of business"?