Speaker 1: Welcome to brain Stuff production of I Heart Radio, Hey
Speaker 1: brain Stuff Lauren Vogelbaum. Here bats fly head first, belly
Speaker 1: down and wings stretched out to the side, just as
Speaker 1: you might expect. So how do they land upside down,
Speaker 1: a position that requires the midair acrobatics of a circus flyer. Well,
Speaker 1: before we answer that question, we first need to look
Speaker 1: at why bats would even want to land upside down.
Speaker 1: To begin with, no other flying animal lands this way.
Speaker 1: Why not just land like birds do with their feet
Speaker 1: firmly under their bodies. The short answer is because bats
Speaker 1: wouldn't be strong enough to take off if they were
Speaker 1: sitting up right. Their wings don't produce enough lift, and
Speaker 1: their legs are too short to run along the ground
Speaker 1: to generate enough speed to get them into the air
Speaker 1: from a head above feet position. Instead, they climb up
Speaker 1: high and literally fall into flying by landing and roosting
Speaker 1: upside down. They're ready to take flight if something threatens
Speaker 1: their sleep. So that's the why. But how do they
Speaker 1: get into this position when they aren't flying very fast
Speaker 1: and they can't cover upside down? It's all about inertia.
Speaker 1: Inertia involves Newton's first law of motion, which says a
Speaker 1: body at rest will stay at rest unless and outside
Speaker 1: force acts on it, and a body and motion will
Speaker 1: continue in a straight line unless acted upon by an
Speaker 1: outside force. And here is where inertia comes in. Inertia
Speaker 1: is proportional to a body's mass, which is the amount
Speaker 1: of matter that a body has. The more mass, the
Speaker 1: more inertia. But how does this relate to bats. Well,
Speaker 1: they don't have much mass, they're small. And here's the thing.
Speaker 1: Bat wings have a lot of mass relative to their
Speaker 1: body size. Their wings have evolved to be made up
Speaker 1: of solid bones and muscles and so are heavier than
Speaker 1: the wings of most are flying critters, which would suggest
Speaker 1: that it might be difficult to get off the ground,
Speaker 1: and it is remember they fall into flight. However, that
Speaker 1: same mass, when acted on by an outside force, such
Speaker 1: as a tiny little movement of the muscles and the
Speaker 1: wings while in motion, will serve to reorient the bat
Speaker 1: and get it upside down. Researchers at the Brown University
Speaker 1: Bat Lab, or as it's officially known, the Aerial Mechanics
Speaker 1: and Evolutionary Morphology Lab A recently studied bat landings using
Speaker 1: cameras to capture the movements of the bats. They discovered
Speaker 1: that as bats got closer to the ceiling of their enclosure,
Speaker 1: they pulled one wing in close to their bodies while
Speaker 1: still flapping the other wing at full extension. This allowed
Speaker 1: the bats to rotate to the right position to land
Speaker 1: feet first on the ceiling. Think about paddling a rowboat
Speaker 1: on just one side of the boat. It makes you
Speaker 1: turn and bats aren't the only animals that exhibit inertial
Speaker 1: re orientation, as the researchers call it. For the article
Speaker 1: this episode is based on How Stuff Works. Spoke with
Speaker 1: study author and principal investigator Sharon Swartz. She said this
Speaker 1: kind of maneuvering is similar to the mechanism used by
Speaker 1: cats to re orient to land on their feet, but
Speaker 1: is also used in many other animals. Geckos move their
Speaker 1: big tails in this way to stabilize themselves during climbing
Speaker 1: and writing. Lemurs use this mechanism in their big jumps.
Speaker 1: We humans employ the sort of movement when gymnasts or
Speaker 1: springboard divers execute somersaults or twists, or when a figure
Speaker 1: skater changes the speed of a spin by changing the
Speaker 1: details of the position of arms or legs. And speaking
Speaker 1: of humans, the United States Air Force helped fund this
Speaker 1: study because sports said quote. Research into the aerodynamics, neural control, biomaterials,
Speaker 1: et cetera of flying animals can give builders of small
Speaker 1: aerial vehicles rich material for their design idea. Y Today's
Speaker 1: episode is based on the article Scientists Solve the Weird
Speaker 1: Physics of How bats land Upside Down on House to
Speaker 1: farks dot Com, written by Karen Kirkpatrick. Brainstuff is production
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