At the moment it is being used for an anniversary exhibition since the zoo turns 150 years this year. It is a very interesting exhibition where visitors look at old pictures and maps as well as movies and scelletons. The visitors are allowed to walk through the old elephant cages as well as the elephant keepers' previous relaxation/break room which as been preserved as it was.
One of my favourite memories of Copenhagen from my single, rather rushed visit was that wonderfully out-of-place and yet somehow so perfectly fitting sauropod silhouette on the elephant house wall! Love it!