When I was there I bought a book called The History of Gladys Porter Zoo. I just did a quick perusal of it, but there is no mention I could find.
However, there is a ZooChatter whose screen name is Show Me Elephants who has a blog of the same name that deals with the history of captive elephants in the USA. Perhaps you will find an answer there or you can just send him or her a PM.
The tall plain walls, foliage-less enclosures and horrid rockwork, makes this zoo feel like an asylum, What an eerie place!
What was your overall impression of Gladys Porter? Seems to have allot of ups and (mostly) downs.
@Nix My only visit to Gladys Porter was in 2010 and the exhibits left a lot to be desired. A huge chunk of the zoo's enclosures still had their basic 1970s framework, although for decades the facility was known for its rarities and so the animal collection was impressive.
