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9 Fantastic Facts About Flying Foxes

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The largest bats on earth are gentle giants with a misleading name. So grab your binoculars, and let’s take a look at these strange and wonderful mammals.

1. There Are Several Dozen Species of Flying Foxes.

More than 60 species currently take wing above Asia, Australia, Africa, and assorted Pacific islands. The fossil record shows theirs is a pretty old group that first evolved at least 35 million years ago.

2. The Biggest Have 5.25-Foot Wingspans.

A native of the Philippines, Acerodon jubatus, the giant golden-crowned flying fox, weighs in at just under 2.5 pounds—about as much as a small pineapple. Another biggie is Pteropus vampyrus, whose wings can stretch 4.92 feet from end to end. Its common name is "large flying fox," which may not be creative, but it is accurate.

3. They're Mostly Vegetarian.

Fruits, leaves, flowers, nectars, and pollen make up the bulk of flying fox diets. As you might expect, some get into trouble with farmers by raiding their fruit trees, though floodlights can be used as a fairly reliable deterrent. Unfortunately, shooting them down is another popular technique in certain areas.

4. They Can’t Echolocate.

Many bats are famous for their ability to emit high-frequency sounds that act as a natural sonar, helping them stalk tasty insects in midair. Flying foxes, on the other hand, lack this talent. Since fruits are stationary, they don’t need it. Instead, the critters use a combination of keen eyesight and a sharp olfactory sense to find breakfast.

5. Colonies Can Be 200,000 Bats Strong.

Come naptime, flying foxes roost in trees, where they form noisy clusters known as camps. When one bat grows restless, he or she will often abandon the clique and fly several miles away in search of new friends to (literally) hang with. But depleted flying fox populations all over the world have made these camps way less impressive than they used to be. As recently as 1930, naturalists happened upon bunches that were 4 miles long and .5 mile wide, and boasted a whopping 30 million bats!

6. Flying Foxes Mate Upside Down.

If you’re going to copulate while dangling from a branch, make sure to mind your footing. Before the deed begins, a female will steady herself by grasping her partner’s ankles with her feet. Meanwhile, the male’s penis might be one-fourth of his total body length. This helps keep it from slipping out mid-coitus, given the delicate logistics involved.

7. On Hot Days, Those Wings Come in Handy.

The bats try to beat the heat by fanning themselves while at rest. When that doesn’t work, flying foxes will seek shade and then lick themselves all over to cool their bodies. Still, above a certain point, extreme temperatures will kill them en masse. Last year, Australia suffered through a blistering summer which claimed the lives of an estimated 100,000 flying foxes in Queensland alone.

8. Mothers Carry Their Babies While Airborne.

A newborn won’t be able to fly on its own for several months. And because these mammals travel from camp to camp in pursuit of food, its mother won't build any permanent nests. Instead, she’ll spend several weeks with her baby bat clinging to her belly; as it grows more independent, mom-bat leaves it behind at night while feeding. Babies are usually born in October and are ready to take off for good by March or April.

9. Flying Foxes are Important Pollinators.

Without their pollinator services, economies around the world would take a serious hit. Consider the durian, a South Asian fruit which generated $440 million in export earnings in Thailand alone last year. Flying foxes enjoy their flowers and play a huge role in the plant’s pollination. Australia’s valuable eucalyptus trees also heavily rely on the bats to reproduce. 

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How Bats Protect Rare Books at This Portuguese Library
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Visit the Joanina Library at the University of Coimbra in Portugal at night and you might think the building has a bat problem. It's true that common pipistrelle bats live there, occupying the space behind the bookshelves by day and swooping beneath the arched ceilings and in and out of windows once the sun goes down, but they're not a problem. As Smithsonian reports, the bats play a vital role in preserving the institution's manuscripts, so librarians are in no hurry to get rid of them.

The bats that live in the library don't damage the books and, because they're nocturnal, they usually don't bother the human guests. The much bigger danger to the collection is the insect population. Many bug species are known to gnaw on paper, which could be disastrous for the library's rare items that date from before the 19th century. The bats act as a natural form of pest control: At night, they feast on the insects that would otherwise feast on library books.

The Joanina Library is famous for being one of the most architecturally stunning libraries on earth. It was constructed before 1725, but when exactly the bats arrived is unknown. Librarians can say for sure they've been flapping around the halls since at least the 1800s.

Though bats have no reason to go after the materials, there is one threat they pose to the interior: falling feces. Librarians protect against this by covering their 18th-century tables with fabric made from animal skin at night and cleaning the floors of guano every morning.

[h/t Smithsonian]

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The Surprising Role Bats Play in Making Your Margarita
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The next time you have a margarita, raise your glass to the humble bat. Long-nosed bats are the main pollinators of agave, the plant used to make both tequila and mezcal. (Tequila is specifically made from blue agave, or Agave tequilana, while mezcal can be made from any species of the plant.) These agave plants open their flowers at night, attracting bats with their sugary nectar, and in turn, the bats help spread their pollen.

One of those bats, the lesser long-nosed bat, just got off the endangered species list in April 2018, as The Washington Post reported. It's the first bat species ever to recover its population enough to be taken off the Endangered Species List. Its revival is due, in part, to tequila producers along the bat's migration route between Mexico and the southwestern U.S. making their growing methods a little more bat-friendly.

While the relationship between bats and agave might be mutualistic, the one between bats and booze isn't necessarily so. Typical agave production for tequila and mezcal involves harvesting the plant right before it reaches sexual maturity—the flowering stage—because that's when its sugar content peaks, and because after the plant flowers, it dies. Instead of letting the plants reproduce naturally through pollination, farmers plant the clones that grow at the agave plant's base, known as hijuelos. That means fields of agave get razed before bats get the chance to feed off those plants. This method is bad for bats, but it's not great for agave, either; over time, it leads to inbred plants that have lower genetic diversity than their cross-pollinated cousins, ones that require more and more pesticides to keep them healthy.

Rodrigo Medellín, an ecologist who has been nicknamed the "Bat Man of Mexico," has been leading the crusade for bat-friendly tequila for decades, trying to convince tequila producers to let some of just 5 percent of their plants flower. The Tequila Interchange Project—a nonprofit organization made up of tequila producers, scientists, and tequila enthusiasts—led to the release of three bat-friendly agave liquors in the U.S. in 2016: two tequilas, Siembra Valles Ancestral and Tequila Ocho, and a mezcal, Don Mateo de la Sierra.

In 2017, when Medellín and his team visited the agave fields of Don Mateo de la Sierra to gather data, they discovered that the project was even more bat-friendly than they thought. The Mexican long-nosed bat, another endangered species, was also taking its meals at the field's flowering plants.

This weekend, raise a glass of tequila to all the bats out there—just make sure it's a bat-friendly brand.

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