Why do bats hang upside down to sleep?

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By sleeping upside down, bats can more quickly prevent predators.
(Image credit: Rapeepong Puttakumwong through Getty Images)

When bats aren’t flying, they typically hang from cavern ceilings or the undersides of bridges. Why do bats sleep upside down?

This topsy-turvy habits might arise from the evolutionary journey bats took towards flight, stated Tara Hohoffa bat biologist and the organizer of the Illinois Bat Conservation Program. “As bats evolved from land-bound mammals to taking flight, they started with gliding like flying squirrels,” Hohoff informed Live Science.

The forefathers of modern-day bats may have climbed up high trees and dropped to move in between the trunks, most likely developing strong limbs for these climbs, Alexander Lewisa bat scientist at California State Polytechnic University, Humboldt, informed Live Science. The effective arms of these sliding animals progressed into wings with time, he discussed.

Since bats do not have hollow bones like birds do, they do not have as much capability for lift throughout flight. Bats still usually “hang upside down to drop into flight,” Hohoff stated.

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The majority of people would discover it challenging to hang from a ledge or any other surface area, whether upside down or right side up. Bats can hang upside down much more quickly than people can because of the method bats’ muscles, tendons and talons have actually developed.

“When a bat finds a place to roost, it contracts muscles attached to its talons, which opens them,” Daniel Pavuka zoologist and the chair of biology at Bowling Green State University in Ohio, informed Live Science. “As the talons touch the roosting surface, the bat relaxes its body. This allows the weight of its body to pull on the tendons connected to the talons.”

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The outcome is that the talons grip the roosting surface area. “The joints of the talons lock, and the weight of the bat’s body keeps the talons closed,” Pavuk stated. Simply put, bats invest very little energy to hang upside down; their bodies are unwinded, and gravity does the work for them.

Unlike human beings, bats can hang upside down for extended periods, according to the Iowa Department of Natural ResourcesWhereas an upturned present would lead blood to swimming pool in an individual’s head, leading to health issue gradually, a bat’s compact size lets its heart quickly pump blood throughout its body.

After hanging upside down ended up being the preferred approach of rest for bats, this brand-new way of life supported the development of a number of other characteristics, Hohoff stated. “the skeletons of bats evolved to be lightweight for flight,” Pavuk stated. “Because of this, their leg bones do not do well supporting their weight for extended periods of time.” By hanging upside down, bats do not need to rest their weight on their weak legs.

Roosting upside down likewise safeguards bats from a few of their prospective predators, Pavuk stated. Hanging from hard-to-reach areas, such as cavern ceilings, can assist them prevent their opponents, such as owls, hawks and snakes

Bats that are on the ground can still remove from a standing position, Pavuk stated. “it is more difficult than initiating flight from a hanging-down position,” he discussed.

Some bats do not solely sleep upside down. “disk-winged bats in Central and South America have special suction cups on their thumbs that they use to adhere to the undersides of leaves, and do so at all sorts of angles,” Lewis stated.

Extra research study into the development of bat flight and the method most bats hang upside down “would be really interesting, since they are the only flying mammals,” Hohoff stated. “There are some species that seem to have an easier time taking off from the ground, so studying what morphologically is different would be helpful to understand.”

Charles Q. Choi is a contributing author for Live Science and Space.com. He covers all things human origins and astronomy along with physics, animals and basic science subjects. Charles has a master of arts degree from the University of Missouri-Columbia, School of Journalism and a bachelor of arts degree from the University of South Florida. Charles has actually checked out every continent in the world, consuming rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing up an iceberg in Antarctica.