"Love can come to everyone
Best things in life, they're free"
- Sam Cooke
Of the hundreds of zoos and aquariums in the United States, there are only a tiny handful - about a dozen - which do not charge admission. Some, surprisingly, are some of the biggest zoos in the country, such as the St. Louis Zoo and Lincoln Park Zoo (the National Zoological Park is also free, as is every part of the Smithsonian Institute). Others, like Illinois' Cosley Zoo and Maryland's Salisbury Zoo, are rather small.
There was a time when many other zoos were free, including many of the large urban zoos (aquariums traditionally have been less likely to offer free admission, considering the higher expenses needed in maintaining aquatic systems). The Pittsburgh Zoo, for instance, used to be free of charge. As times began to get tougher, the zoo began to charge admission to individual exhibits - an entry free for one building, a separate fee for another. Finally, the addition of the zoo's aquarium was deemed to be a significant enough change that the whole system of nickel-and-diming was done away with and a flat admission fee was instituted.
I've worked at free zoos, at non-profit zoos that charged admission, and at for-profit, private zoos. There are definitely things that I do like about not charging admission. For one thing, it allows the entire community - including the less affluent members - to enjoy the zoo. Anyone can come and learn about the animals and be inspired by them, not just those who can afford admission. It also takes some of the pressure of expectations off of the zoo; there are no angry visitors complaining that they spent money to come in and their favorite animals are off exhibit, or sleeping out of sight, or it started raining thirty minutes after they arrived. Being free of admission usually also means that the zoo has a funding source from elsewhere, which means that it might be more financially secure than other institutions.
At the same time, there are definite advantages to a gate fee. For one thing, there is security... if anyone can come in, then everyone can come in... including trouble makers. Everything from rowdy, unsupervised teenagers to drug dealers and prostitutes to homeless persons with serious mental health issues... all in the day's work at one free zoo where I worked. With no admission fee there may end up being no front gate staff (there to sell tickets at other zoos), which deprives the facility of its first line of security (stray dogs being another problem).
A slightly more nebulous problem is a question of the zoo's value. This goes two ways. Sometimes, I feel that if people don't pay for something, they don't value it. Being free sometimes also creates the impression among staff that they don't "owe" anything to the visitors. If something is broken, or untidy, or an animal is off exhibit all the time, then they shrug and say "You get what you pay for." "Did you want your ticket refunded?", was the particularly smug reply one keeper I knew would use when dealing with complaints at a free zoo where we worked.
Some zoos have tried having the best of both worlds by having "free days." In my experience, this usually ends up as a disaster, as all of the problems with being free still occur, just condensed into a few days of the year. This can result in major safety issues as a facility becomes very quickly crowded to a degree that the zoo can have difficult managing (evidence: Kansas City Zoo's free day fiasco).
In my perfect world (which does not, has not, and never will exist) everyone would visit the zoo or aquarium often, and they would do so free of charge. They would support the institution with their own donations, going towards both the upkeep and advancement of the institution, as well as supporting conservation projects through those institutions. Until then, the tiny handful of free zoos left in the country remain that much more valuable... and I'll just drop an extra dollar or two in the donation box as I walk through the gate.