Changing role, hard decisions
Zoos - the good ones, anyway - have moved to embrace their pivotal role in conservation and the breeding of endangered species and prioritize that over the old idea of having examples of as many species as possible. In my home of Colorado Springs, this means the Cheyenne Mountain Zoo keeps a breeding colony of black-footed ferrets and a family of Amur leopards, among other things. But for all zoos, it means making hard choices. Given that budgets have ceilings, zoos housing endangered species have to choose. Some species are not going to be chosen, and their captive populations will die out. Also, there is no getting around the fact that zoos have to attract the public, a point the St. Louis Zoo makes about keeping its non-endangered camels (who don't mind being outdoors and thus visible all year round) and spending $18M on a new pool for sea lions (not endangered in the wild, but wildly popular with visitors). I don't envy zookeepers who are trying to walk this tightrope.