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9 Fantastic Facts About Flying Foxes

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istock

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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Deb Wright
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Animals
The ‘Yoda Bat’ Gets an Even Cuter Name
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Deb Wright

The fruit bat formerly known as Yoda has found its forever name. Scientists christened the happy tube-nosed fruit bat in the Records of the Australian Museum.

The genus Nyctimene comprises 18 species, all of which live in Oceania and southeast Asia. They’ve got bright fur and faces, and noticeable spots on their wings. They will do just about anything for a mushy piece of fruit.

The family tree is no stranger to memorable common names, with cousins like N. draconilla, the dragon tube-nosed bat, and N. masalai, the demonic tube-nosed bat.

But wacky names aside, it would be hard to spot the dragon or the demon amid a lineup of other Nyctimene species.

“Bat species often look similar to each other,” biologist and co-author Nancy Irwin of York University said in a statement, “but differ significantly in behavior, feeding, and history.”

The newest member of the family showed its smiling little face during a field survey of Papua New Guinea in the late 1990s. Surveyors brought the bat to Irwin, who suspected it was a separate species. For its wrinkly ears and sage but goofy smile, she nicknamed the bat Yoda.

To confirm that they did, in fact, have a new species on their hands, Irwin and her colleagues combed through the scientific literature and museum collections. They examined nearly 3000 bat specimens from 18 museums.

A happy tube-nosed fruit bat with her baby and a postage stamp featuring an illustration of an unknown tube-nosed fruit bat.
Happy tube-nosed fruit bat (L) and a postage stamp (R) showing an unknown Nyctimene species, because they all look the same.
(L) Nancy Irwin; (R) Illustration by Julie Himes.

Many years and many, many research hours later, Irwin and her colleagues can confidently say the Yoda bat is a species unto itself. But they won’t call it Yoda anymore—since, as Irwin points out, most local Papuans have never seen the Star Wars movies, and the word "Yoda" means nothing to them.

She went with Hamamas (a local word for happy) instead. Its full name is the Hamamas tube-nosed fruit bat, Nyctimene wrightae sp. nov. (new species). The species name was chosen in honor of conservationist and scientist Deb Wright, who spent two decades exploring and protecting Papua New Guinea wildlife.

“Until a species is recognized and has a name,” Irwin says, “it becomes difficult to recognize the riches of biodiversity and devise management. Fruit bats are crucial to rainforest health, pollinating and dispersing many tree species, therefore it is essential we know what is there and how we can protect it, for our own benefit.”

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SMBishop, Wikimedia Commons // CC BY-SA 3.0
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Animals
Bats Yell, Too
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SMBishop, Wikimedia Commons // CC BY-SA 3.0

Imagine you’re in a noisy restaurant, trying and failing to place an order. “IT’S VERY LOUD IN HERE!” you shout to your server, who shrugs. Now imagine that same conversation conducted super-fast, at a pitch so squeaky-high that you can’t even hear it. Researchers say bats are incredibly speedy at recognizing when they need to start shouting. A report on the bats’ raised voices is forthcoming in the Proceedings of the National Academy of Sciences.

Humans, bats, and other animals often start our conversations at one volume, then adjust as necessary. Study co-author Ninad Kothari of Johns Hopkins University says this seemingly simple action, called the Lombard effect, has proved complicated to understand.

“Scientists have been wondering for a century—could there be a common auditory process to explain how this phenomenon happens in fish to frogs to birds to humans, species with wildly different hearing systems?” Kothari said in a statement.

Previous studies had found that the Lombard effect takes about 150 milliseconds for birds and bats, and between 150 and 175 milliseconds for people.

Human listening, like human speech, can be messy, slow, and difficult to study. But bats’ echolocation squeaks and chirps are quick and precise, which makes them excellent scientific subjects.

Kothari and his colleagues Jinhong Luo and Cynthia Moss, also of Johns Hopkins, trained big brown bats (Eptesicus fuscus) to sit calmly on little platforms surrounded by recording equipment. The researchers set up an automated pulley system that brought insects zooming toward the bats, then listened as the bats hunted, bouncing sound off the approaching meal. Sometimes they let the bats go about their business in silence; other hunting sessions were interrupted by bursts of loud white noise.

The results suggest that earlier speed estimates had been way, way off. Just 30 milliseconds after hearing white noise, the bats got louder. That’s a “remarkably short” reaction time, the authors say.

“Typically, we breathe every three to five seconds, our heart beats once per second, and eye blinking takes one-third of a second,” Luo said in the statement. “If we believe that eye blinking is fast, the speed at which an echolocating bat responds to ambient noise is truly shocking: 10 times faster than we blink our eyes.”

Not bad, bats. Not bad.

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