The Books In Historic Portuguese Library 'Biblioteca Joanina' Have The Most Unusual Guardians — Bats

Books are a storehouse of history and knowledge that humanity has acquired over centuries. However, they are not easy to protect from beetles and moths, which often leads to important historical information getting completely lost. For books inside Biblioteca Joanina at the University of Coimbra, Portugal, that is fortunately not the case because of a mammal, stated My Modern Met. 

The friendly mammals are none other than bats. Bats and books don't sound like a good combination, but for decades, these mammals have proven to be great protectors of several valuable collections inside the prestigious 18th-century library. The bats come out every night from their hidden corners and attack the beetles and moths present in the establishment. The bats are so efficient in their work that the library officials have facilitated many changes in the library to accommodate their presence.

In the 19th century, library officials brought large leather sheets from Russia and put them over desks to protect them from bat droppings. Today, the same method is applied to furniture, with workers coming every morning to wipe off droppings, if any, from the sheet. The windows are also deliberately left open every night to allow bats to roam in the garden and drink water. The presence of bats in the library has been recorded for around three centuries. 

In 2015, when the library's enormous wooden doors were replaced, authorities ensured that the carpenters kept the gaps of the past in their new installation, stated Atlas Obscura. These gaps were possibly used by the bats to enter and leave the library. Though there is no confirmation, considering how seamlessly the bats work to protect the books, some think that they were introduced by the original builders. Library’s deputy director, António Eugénio Maia do Amaral calls the bats 'honorary librarians.'

These bats are hard to encounter during the day, ensuring that the visitors have a smooth experience, stated My Modern Met. There have been some times in rainy seasons when librarians have noted the stirring of bats, during which the mammals produce squaks or chirps, which often come out as a song. The library also organizes evening concerts, where visitors are very likely to come face-to-face with the flying predators, because it coincides with their dinner time. There are two bat colonies in Biblioteca Joanina, one of which houses European free-tailed bats, while the other has soprano pipistrelle. 

Along with being the library that hosts books and bats, Biblioteca Joanina is also known worldwide as Portugal's oldest library. It has been identified as having elements of Baroque architecture. The whole place has an expansive decor. It exhibits several ornate balconies, gilded arches dividing many rooms, and two-story bookshelves. Experts noted that the monumental facade of the library is composed of white and earthy tones, while decorative pillars surround the entrance to the facility.  Apart from Biblioteca Joanina, there is only one other library that houses bats along with books. The other one is a 300-year-old establishment at the National Palace of Marfa. This place is inhabited by grey long-eared bats and some serotine bats, as per experts.