Given the recently published split in this species (see https://www.biotaxa.org/Zootaxa/article/view/zootaxa.5219.4.5 ), I wonder which of the two taxa Burgers actually have. I suppose the only way to check would be the zoo carrying out a morphological and/or genetic study, the differences are not really pronounced enough to be able to judge from photos of single individuals.
@Swampy A zoo employee indeed mentioned a while back that it could well be a different species, but they don't know either.
@Mr Gharial They are in fact very easy if you know where to look... But I hesitate to post where and how to see them, as when not done carefully it could be destructive...