In the walls of the University of Coimbra in Portugal lies the Biblioteca Joanina. This 18th-century baroque library is not only renowned for its opulent interior and precious collections but also for its unique, nocturnal caretakers – bats.
These bats actually play a crucial role in the preservation of this historic library’s books.
Guardians of the Biblioteca Joanina
Every night, after the sun sets and the doors close, the Biblioteca Joanina becomes the domain of small, insect-eating bats. Hidden from the library’s visitors, these bats embark on their nightly feasts, hunting the insects that could otherwise damage the library’s ancient manuscripts.
This natural pest control method has been in place for centuries, a secret pact between the bats and the library, protecting the invaluable collection without the use of chemicals.
A Symbiotic Relationship
The bats in the Biblioteca Joanina are not just tolerated; the caretakers welcome and accommodate them. Before closing time, staff lay out leather covers to protect the historic tables from bat droppings.
Each morning, these are cleaned up, ensuring that the library remains pristine for its human visitors. This routine highlights a remarkable symbiotic relationship. The bats receive shelter and hunting ground, while the library gets a highly effective, eco-friendly pest management service.
The main adversaries of the Biblioteca Joanina’s collection are book-eating insects like silverfish and booklice. These creatures thrive in the organic materials of the books. The bats, by keeping the insect population in check, help preserve these texts in a way that few modern methods can.
However, this unique method of preservation does not come without its challenges. The acidity in bat guano, for instance, can be harmful if not regularly cleaned. It requires diligent maintenance by the library staff.
The Secret of the Biblioteca Joanina’s Bats
The bats of the Biblioteca Joanina are a species adept at navigating the tight spaces and dark nooks of the library, making them perfect for this environment. Their ability to use echolocation allows them to hunt with precision in complete darkness, ensuring that their nightly patrols are successful. This adaptation is key to their role as protectors of the library’s collection, demonstrating nature’s ingenuity.
While visitors seldom see the bats themselves, their presence adds a layer of mystique to the Biblioteca Joanina. Tour guides often share tales of these nocturnal guardians, enchanting visitors with stories of how nature and culture can coexist.
This has turned the library into a place of legend. Today, it attracts tourists not only for its architectural beauty and historical significance but also for its unique, bat-inhabited halls.
Source: “These Portuguese Libraries Are Infested With Bats—and They Like It That Way” — Smithsonian Magazine