The Test of Time

 When I was making my most recent Sporcle quiz, US Zoos and Aquariums by Exhibit, I was caught up in the details of picking which exhibits would be the most iconic to represent each facility.  Some of them were brand spanking new, the newest of them having just opened last year.  Others go back decades.  If I'd tried, I probably could've even named one or two that were over a century old (for example, the iconic 1904 World's Fair Flight Cage, since rebranded as the Cypress Swamp, at the St. Louis Zoo).

If I were to have hopped over to Europe, I could have found even older exhibits.  Some of these older zoo exhibits are still in use to excellent effect.  Elsewhere, I could point out exhibits that are much newer and opened with great fanfare, but were considered mediocre and in some cases were dropped within years of their opening.

What makes a zoo exhibit timeless, able to continue in usage for decades?

I think a key provision is space.  A lot of zoo exhibits become obsolete or are replaced because they no longer are considered spatially appropriate for the animals that are housed in them, and must be cleared away to create new, larger habitats.  (Conversely, the habitat could be kept, but the occupants changed to be species that don't require as much space).    A successful exhibit will build not for the present and its requirements, but for the future, with the idea that standards of animal care will evolve over time.  In other words, take the biggest space you think you may need.  Than, make it bigger.

Another design feature I would recommend is planning for future maintenance.  All exhibits age and will need repairs, be it the replacing of furniture or the addition of new features, or, for exhibits with aquatic features, changes to filtration and life support systems.  If there is no way to upgrade those features without destroying the exhibit, then the exhibit will not survive for future use.  (Some exhibits seem to have undergone a "Ship of Theseus" renovation process over the years, with so many upgrades and renovations that one could ask if they really are the same exhibit anymore).

Remarkably few exhibits can really be said to pass the test of time.  At my own zoo, I can only think of a small number of exhibits that predate my birth and still house the animals that they were built for.  None of the exhibits that were there when my parents were children are still standing with the species that they were built for, and those few that remain from that age are all heavily modified, either renovated several times or with much different (smaller) animals in them.

At Carl Hagenbeck's zoo outside Hamburg, Germany, lions watch grazing antelope from across a hidden moat, just as their predecessors would have done nearly 120 years ago.  Even older exhibits occur elsewhere in Europe (at least where the destruction of WWII didn't wipe them from the map).  I wonder which exhibits we build today (if any) will be standing in their original form 100 years from now.