October 24, 2016

It haunts caves, crevices, and tunnels by day, emerging only at night to look for victims. You probably would not hear it flying above your head, but you might catch a glimpse of its whitish fur flashing in the moonlight… It is the ghastly ghost bat of Australia.

Australia’s ghost bat. Credit: Liz Lawley (licensed under CC BY-SA 2.0)

Take one look at the ghost bat and you will understand its name. Its large, midnight-black eyes give it a spooked look and, in some regions, its fur is ghoulishly pale. It has large, filmy ears and a leaflike nose poking out from its creepy-looking head. Like many bats, however, ghost bats are almost cute—and not terribly big. An adult can reach about 5 inches (13 centimeters) in length, and its milky, clear wings can spread to about 20 inches (50 centimeters).

The ghost bat is one of the most carnivorous (flesh-eating) of all bats. The diets of most other bat species (kinds) consist of fruit, insects, or sometimes the blood of living animals. The ghost bat, however, specializes in eating frogs, lizards, birds, and other small animals. With a swift and silent swoop, it drops onto its prey, enclosing the victim in its wings and killing it with bites to the head and neck. It then flies to an eating spot, carrying the entire animal with its feet. A ghost bat can kill and carry prey that weighs up to 80 percent of its own weight. When it is time to eat, the ghost bat will consume nearly every part of its victim, including bones, fur, and feathers.

The thought of ghost bats gliding in the night might be spine-tingling, but like other bats, their fearsome reputation is mostly undeserved. Ghost bats do not attack human beings and will avoid contact with people if they can. In fact, ghost bats are vulnerable to the destruction and disturbances humans create in the bats’ natural habitat. Repeated visits by humans can cause a colony of ghost bats to abandon a cave, and mining activities have destroyed many of their roosting sites. Because these bats often rely on vision and hearing more than echolocation during flight, they often die from crashing into such hard-to-see obstacles as barbed wire fences and electric power lines. In echolocation, a bat uses echoes of sounds it produces to collect information about its surroundings. Ghost bats also often fall prey to hunting cats and foxes. It is up to people to save our small, spooky friends by protecting the caves, tunnels, and hunting grounds that ghost bats call home.

Monster Monday

January 4, 2016

In nature’s beauty contest, bats are seldom winners. But even the homeliest vampire bat is easy on the eye compared to this Monday’s monster: the wrinkle-faced bat. As the name implies, the bat’s largely hairless face has a deeply wrinkled texture. We’re not talking about a few frown lines or crow’s feet, either. The wrinkles and folds of skin are so deep it can be difficult to distinguish the animal’s tiny nose. Compared to other bats, the wrinkle-faced bat also has a wide, shallow face with large eyes.

The wrinkle-faced bat measures up to 2 ¾ inches (7 centimeters) in length. It lives mostly in the forests of southern Mexico and Central and South America. Credit: © Roy Fontaine, Photo Researchers

Wrinkle-faced bats are fairly tiny monsters, measuring up to 2 ¾ inches (7 centimeters) in length. Their bodies are covered in brown to gray fur, and they even have a “beard” of white fur to complete their wizened look. The bat’s scientific name, Centurio senex, is a play on words that compares the animal’s appearance to that of a 100-year-old man.

Wrinkle-faced bats live mostly in the forests of southern Mexico and Central and South America. During the day, they roost in trees alone or in small groups. At night, they hunt for food. If you ever encounter this monster, you risk little beyond a fright—wrinkle-faced bats are fruit eaters. They prefer overripe fruits such as bananas and mangos, biting into the softened flesh and sucking out the juices. Their wide, shallow skulls give them enhanced bite strength, which they probably use to dine on tougher fruit when soft meals are scarce.

Nobody knows exactly what purpose such a deeply wrinkled face serves. Many bats navigate in the dark using echolocation. In this process, the bat emits high-pitched sounds and listens for the echoes, forming an impression of its surroundings. The folds and flaps of skin may help the wrinkle-faced bat to focus sounds for this purpose. Males also use scent glands located in the folds to attract mates. They even have a “mask” of skin that can be pulled over the face while resting.

Other World Book articles: 

•  The Real Life Vampire: The Vampire Bat (Oct. 26, 2015) – A Behind the Headlines article

Monster Monday

October 26, 2015

Vampire bat (c) Stephen Dalton, Photo Researchers

As Halloween approaches, people spook one another by talking about or dressing like vampires. But you can really freak out your friends with tales of a real life vampire: the vampire bat.

Three species of vampire bat live in Central and South America. As the name suggests, the bat survives by drinking blood, usually from cattle, fowl, or horses. Vampire bats have been known to feed on people, but only in rare cases.

A vampire bat homes in on its next meal by listening for the measured breathing of a sleeping animal. Then, it sneaks up along the ground. As bats evolved (developed over time) to master flight, most of them lost the ability to move along the ground. But the vampire bat pulls itself along with its powerful wings, a unique gait that allows walking, running, and even jumping.

Special heat receptors on the bat’s nose help it locate a spot where the blood flows close to the surface. Then the bat gently slices into the animal’s skin with razor sharp teeth, lapping up the spilling blood with its tongue. Special chemicals called anticoagulants (an tee koh AG yuh luhntz) in the bat’s saliva help to prevent clotting and keep the blood flowing.

Blood is mostly water, and water is quite heavy, so a good meal can really weigh down a vampire bat, preventing flight. To accommodate this, the bat has evolved the ability to process fluids quickly. Plasma, the fluid portion of blood, absorbs rapidly through the stomach walls and is sent to the kidneys, to be released in urine. This release begins as little as two minutes after the bat starts feeding.

Drinking the blood of other animals may make the vampire bat seem cruel or frightful, but the creature is only acting naturally. Aside from drinking blood, vampire bats do have a fairly unique and helpful—if seemingly distasteful—social behavior. A vampire bat needs to eat every couple of days to stay alive. If an individual misses a meal, another bat may help out, sharing food by regurgitating (throwing up) some of its meal into the starving bat’s mouth.