Bats in libraries

Some impressive interiors in this collection of The world’s most beautiful libraries. This caption also intrigued me –

one of only two libraries in the world that houses bats to protect the books against insects

so I had to investigate further

the bats, which are less than inch long, roost during the day behind “elaborate rococo bookcases” and come out at night to hunt insects which otherwise would feast on the libraries’ books. The price of this natural insect control is paid in scat; the bats […] leave a thin layer of droppings over everything. So each morning the floors have to be thoroughly cleaned and the furniture has to be covered at night.