Very interesting photo. Presumably the Gorillas were in residence. Is that one at the extreme left, halfway up the bars?- people have gathered to look at something. I can see just three ropes hanging down, otherwise it looks completely bare.
This is the Berthold Lubetkin Gorilla House (1932-33) so I'd guess the photo was taken around that time or soon after .... amazing what a bit of Googling can bring up ! However, without looking anything up, I would have guessed late 1920s, early 1930s, from the style of clothing visible ..... all the men with hats on for example !
