The Guardian newspaper has a review of Zoo Buildings: Construction and Design Manual, by Natascha Meuser, which is a history of all forms of animal enclosures – cages, menageries, bear pits, zoological gardens, fake ‘natural’ landscapes. Although the review doesn’t mention them specifically, I assume Meuser also deals with London Zoo’s Mappin Terraces, which provide the main reference point for Saki’s story ‘The Mappined Life’.