WEBVTT - Why Do Bats Land Upside Down?

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<v Speaker 1>Welcome to brain Stuff production of I Heart Radio, Hey

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<v Speaker 1>brain Stuff Lauren Vogelbaum. Here bats fly head first, belly

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<v Speaker 1>down and wings stretched out to the side, just as

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<v Speaker 1>you might expect. So how do they land upside down,

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<v Speaker 1>a position that requires the midair acrobatics of a circus flyer. Well,

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<v Speaker 1>before we answer that question, we first need to look

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<v Speaker 1>at why bats would even want to land upside down.

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<v Speaker 1>To begin with, no other flying animal lands this way.

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<v Speaker 1>Why not just land like birds do with their feet

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<v Speaker 1>firmly under their bodies. The short answer is because bats

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<v Speaker 1>wouldn't be strong enough to take off if they were

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<v Speaker 1>sitting up right. Their wings don't produce enough lift, and

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<v Speaker 1>their legs are too short to run along the ground

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<v Speaker 1>to generate enough speed to get them into the air

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<v Speaker 1>from a head above feet position. Instead, they climb up

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<v Speaker 1>high and literally fall into flying by landing and roosting

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<v Speaker 1>upside down. They're ready to take flight if something threatens

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<v Speaker 1>their sleep. So that's the why. But how do they

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<v Speaker 1>get into this position when they aren't flying very fast

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<v Speaker 1>and they can't cover upside down? It's all about inertia.

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<v Speaker 1>Inertia involves Newton's first law of motion, which says a

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<v Speaker 1>body at rest will stay at rest unless and outside

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<v Speaker 1>force acts on it, and a body and motion will

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<v Speaker 1>continue in a straight line unless acted upon by an

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<v Speaker 1>outside force. And here is where inertia comes in. Inertia

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<v Speaker 1>is proportional to a body's mass, which is the amount

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<v Speaker 1>of matter that a body has. The more mass, the

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<v Speaker 1>more inertia. But how does this relate to bats. Well,

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<v Speaker 1>they don't have much mass, they're small. And here's the thing.

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<v Speaker 1>Bat wings have a lot of mass relative to their

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<v Speaker 1>body size. Their wings have evolved to be made up

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<v Speaker 1>of solid bones and muscles and so are heavier than

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<v Speaker 1>the wings of most are flying critters, which would suggest

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<v Speaker 1>that it might be difficult to get off the ground,

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<v Speaker 1>and it is remember they fall into flight. However, that

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<v Speaker 1>same mass, when acted on by an outside force, such

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<v Speaker 1>as a tiny little movement of the muscles and the

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<v Speaker 1>wings while in motion, will serve to reorient the bat

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<v Speaker 1>and get it upside down. Researchers at the Brown University

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<v Speaker 1>Bat Lab, or as it's officially known, the Aerial Mechanics

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<v Speaker 1>and Evolutionary Morphology Lab A recently studied bat landings using

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<v Speaker 1>cameras to capture the movements of the bats. They discovered

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<v Speaker 1>that as bats got closer to the ceiling of their enclosure,

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<v Speaker 1>they pulled one wing in close to their bodies while

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<v Speaker 1>still flapping the other wing at full extension. This allowed

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<v Speaker 1>the bats to rotate to the right position to land

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<v Speaker 1>feet first on the ceiling. Think about paddling a rowboat

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<v Speaker 1>on just one side of the boat. It makes you

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<v Speaker 1>turn and bats aren't the only animals that exhibit inertial

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<v Speaker 1>re orientation, as the researchers call it. For the article

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<v Speaker 1>this episode is based on How Stuff Works. Spoke with

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<v Speaker 1>study author and principal investigator Sharon Swartz. She said this

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<v Speaker 1>kind of maneuvering is similar to the mechanism used by

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<v Speaker 1>cats to re orient to land on their feet, but

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<v Speaker 1>is also used in many other animals. Geckos move their

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<v Speaker 1>big tails in this way to stabilize themselves during climbing

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<v Speaker 1>and writing. Lemurs use this mechanism in their big jumps.

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<v Speaker 1>We humans employ the sort of movement when gymnasts or

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<v Speaker 1>springboard divers execute somersaults or twists, or when a figure

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<v Speaker 1>skater changes the speed of a spin by changing the

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<v Speaker 1>details of the position of arms or legs. And speaking

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<v Speaker 1>of humans, the United States Air Force helped fund this

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<v Speaker 1>study because sports said quote. Research into the aerodynamics, neural control, biomaterials,

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<v Speaker 1>et cetera of flying animals can give builders of small

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<v Speaker 1>aerial vehicles rich material for their design idea. Y Today's

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<v Speaker 1>episode is based on the article Scientists Solve the Weird

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<v Speaker 1>Physics of How bats land Upside Down on House to

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<v Speaker 1>farks dot Com, written by Karen Kirkpatrick. Brainstuff is production

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<v Speaker 1>of I Heart Radio in partnership with hous towarks dot

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