High above the Mondego River, in Portugal’s interior, a colony of common pipistrelles bats wings out of a library, soars over the cobbled university square, and disappears into the night. These are perhaps the most famous residents of the University of Coimbra. By day, they doze in the stacks of the European baroque Joanina Library, home to such ancient works as the first edition of Dionysius of Halicarnassus’s Roman Antiquities and Homer’s Opera Omnia. Come nightfall, they emerge to feed on flies and gnats and other pests within the library, before swooping out the windows in search of water. Every evening, the librarians here—some who claim they can even hear the bats “singing” late in the afternoon on days when the weather changes rapidly to rain—cover the library’s 18th-century tables with a heavy animal-skin fabric. Every morning, they wash away whatever droppings the bats have left behind.
Bats have been in residence at the Joanina Library since at least the 19th century, perhaps longer: The librarians know this because they still hold the receipt for that protective fabric that was imported from Russia 200 years ago. Today, as then, the effect of these flittermice, combined with difficult-to-penetrate oak bookcases decorated meticulously in Chinese motifs, is an environment nearly free of destructive bookworms, so to speak.
For the average visitor, catching a glimpse of the nocturnal sprites isn’t always easy, but stand on the steps leading from the library to that cobbled square on any given night and, if you’re lucky, you may just catch a glimpse.
Strangely enough, Coimbra’s Joanina isn’t the only Portuguese library with bats. To the south, in Mafra, a small colony of bats swoops among incunabula (books printed prior to 1501) at the 18th-century Library at the National Palace of Mafra before flitting out into the near-seaside air. The Enlightenment-era library pays tribute to them inside with a small exhibition: In a glass case rest the taxidermized remains of three different bats.
The library—considered among Europe’s most important, with its 36,000 books and ancient manuscripts, including the 1493 Nuremberg Chronicle and scores from musicians such as João de Sousa Carvalho—is itself impressive to behold. Laid out on a cross-shaped footprint, the rococo-style main room is lined from end to end with ornate, open-faced bookshelves, all set atop rose, white, and gray marble tiled floors. If the library looks oddly familiar, that’s because it served as the Lilliputian Great Chamber of War in the 1996 film version of Gulliver’s Travels.
Come for the bats, but stay and roam the palace for the array of other oddities and exhibits: It is also home to six pipe organs, galleries full of sculptures and paintings by Italian and Portuguese masters, and 156 stairways.
Libraries aren’t the only cultural institutions bats have turned into homes. At St. Fagans National Museum of History, on the outskirts of Cardiff, Wales, hundreds of bats cavort in the night sky. Up to 10 species live on the grounds of the 16th-century St. Fagans Castle and gardens, as well as in the historic buildings, acquired from across the country, which reveal how people lived and worked in Wales from prehistoric times to the present. On view are the remains of a young Neanderthal boy who lived in Wales 230,000 years ago, Iron Age roundhouses, and a community bread kiln from the early 1800s. The bats, meanwhile, roost in the ancient farmhouses, an 18th-century tannery, a medieval church, and a newly constructed bat tower. The largest colony hangs above a 1960s administration building.
While most of the bats migrate to hibernate elsewhere come winter, by spring they return to St. Fagan’s and to the tannery especially, where they raise their pups each year.
“We think there are around 9 or 10 species of bat at the museum at the moment, which is a high number as there are only 18 species in the U.K.,” says Hywel Couch, the museum’s senior learning, participation, and interpretation officer. “I’ve worked at the Museum for 13 years and I’ve always known that there were bats here. I think as soon as the museum started moving old buildings from across Wales to the site, the bats probably moved in to some of them. As the museum is surrounded by woodlands, it’s probable that many of the bat species would have been here before the museum.”
To offer visitors a glimpse, St. Fagans leads five bat walks in August that begin around sunset. The first stop is the administration block to watch the soprano pipistrelles emerge for the night. From there, it’s on to the maternity ward in the Rhaeadr Tannery, where the mothers and pups roost, among them the tiny, endangered Lesser Horseshoe bat. Then it’s off to the ponds to watch pipistrelle and daubenton bats feed on insects above the water. Throughout the 90-minute torch-lit tour, visitors can see the bats capering in the Welsh night sky and hear them, too, by using a listening device that converts the echolocation ultrasound signals emitted by the bats to frequencies audible to the human ear.
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