Define "Zoo"

On the same trip through southern California that took me to the Aquarium of the Pacific, the Cabrillo Marine Aquarium, and the Los Angeles Zoo, I once split an afternoon between two very interesting institutions literally next door to one another.  One is the Natural History Museum of Los Angeles County.  The other is the California Science Center.  

The former is a very nice, comprehensive natural history museum with fossils, taxidermy mounts, and minerals.  It also has a small collection of live animals, both insects and arachnids in a bug zoo, as well as a small lab space on the ground floor with a handful of snakes, turtles, and other small native creatures.  The later is a general kid-friendly science museum, with exhibits on a variety of topics (not least of all a space shuttle), but also some small exhibits of wildlife, from Malagasy geckos to fennec foxes, as well as an aquarium section.

Kelp forest display in the aquarium at the California Science Center

There was a lot that I'd wanted to do in Los Angeles that day, and while I definitely would have hit the Natural History Museum (I'd been to its sister facility at the La Brea Tar Pits earlier that day)  I might not have given the Science Center much thought if I hadn't known that it was an accredited member of the Association of Zoos and Aquariums.   The Natural History Museum is not, nor would have I expected it to be, what with the small size of its animal collection.

That did raise a thought for me - at what point does a facility that houses and displays animals become a zoo or aquarium?  Is there a size limit?  A proportion of the collection that is live animals versus other exhibits?  The National Museum of Natural History in Washington, DC has a live insect and arachnid collection; they call it the Insect Zoo, but I never really thought of it as a zoo.  Does it matter what the breakdown is in native versus exotic species?  If so, where is the cut off from a small local nature center versus a facility that specializes in native wildlife, as Cabrillo Marine Aquarium does?  I've gone into pet stores without any intention of buying things before, but just to look at the birds, herps, and fish, especially at specialty stores with lots of novel species.  That sounds sort of zoo-ish, but it's not, is it?

A friend of mine is a docent at a museum that has a few small animal displays.  He wanted me to help him encourage his boss to apply for AZA accreditation.  I tried explaining that the cost and effort that would go into that process far, far outweighed any benefit the facility would obtain.  They wouldn't be participating in breeding programs or swapping animals.  It would be a nice validation of their level of animal care, but animal care is only one part of the accreditation process.  I don't need AZA to come to my home to tell me how well I'm caring for my pets.

So, there is a line somewhere.  I just have trouble seeing exactly where it is.

Western pond turtle at Natural History Museum of Los Angeles County