Why Do Bats Land Upside Down?

Bats take off and land from an upside-down position -- and researchers have figured out how (and why) they accomplish this. Learn more in today's episode of BrainStuff, based on this article: https://animals.howstuffworks.com/mammals/how-bats-land-upside-down.htm

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Episode Transcript

Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio, Hey
brain Stuff Lauren Vogelbaum. Here bats fly head first, belly
down and wings stretched out to the side, just as
you might expect. So how do they land upside down,
a position that requires the midair acrobatics of a circus flyer. Well,

(00:25):
before we answer that question, we first need to look
at why bats would even want to land upside down.
To begin with, no other flying animal lands this way.
Why not just land like birds do with their feet
firmly under their bodies. The short answer is because bats
wouldn't be strong enough to take off if they were
sitting up right. Their wings don't produce enough lift, and

(00:47):
their legs are too short to run along the ground
to generate enough speed to get them into the air
from a head above feet position. Instead, they climb up
high and literally fall into flying by landing and roosting
upside down. They're ready to take flight if something threatens
their sleep. So that's the why. But how do they

(01:09):
get into this position when they aren't flying very fast
and they can't cover upside down? It's all about inertia.
Inertia involves Newton's first law of motion, which says a
body at rest will stay at rest unless and outside
force acts on it, and a body and motion will
continue in a straight line unless acted upon by an

(01:30):
outside force. And here is where inertia comes in. Inertia
is proportional to a body's mass, which is the amount
of matter that a body has. The more mass, the
more inertia. But how does this relate to bats. Well,
they don't have much mass, they're small. And here's the thing.
Bat wings have a lot of mass relative to their

(01:52):
body size. Their wings have evolved to be made up
of solid bones and muscles and so are heavier than
the wings of most are flying critters, which would suggest
that it might be difficult to get off the ground,
and it is remember they fall into flight. However, that
same mass, when acted on by an outside force, such

(02:12):
as a tiny little movement of the muscles and the
wings while in motion, will serve to reorient the bat
and get it upside down. Researchers at the Brown University
Bat Lab, or as it's officially known, the Aerial Mechanics
and Evolutionary Morphology Lab A recently studied bat landings using
cameras to capture the movements of the bats. They discovered

(02:36):
that as bats got closer to the ceiling of their enclosure,
they pulled one wing in close to their bodies while
still flapping the other wing at full extension. This allowed
the bats to rotate to the right position to land
feet first on the ceiling. Think about paddling a rowboat
on just one side of the boat. It makes you
turn and bats aren't the only animals that exhibit inertial

(02:59):
re orientation, as the researchers call it. For the article
this episode is based on How Stuff Works. Spoke with
study author and principal investigator Sharon Swartz. She said this
kind of maneuvering is similar to the mechanism used by
cats to re orient to land on their feet, but
is also used in many other animals. Geckos move their

(03:20):
big tails in this way to stabilize themselves during climbing
and writing. Lemurs use this mechanism in their big jumps.
We humans employ the sort of movement when gymnasts or
springboard divers execute somersaults or twists, or when a figure
skater changes the speed of a spin by changing the
details of the position of arms or legs. And speaking

(03:43):
of humans, the United States Air Force helped fund this
study because sports said quote. Research into the aerodynamics, neural control, biomaterials,
et cetera of flying animals can give builders of small
aerial vehicles rich material for their design idea. Y Today's

(04:05):
episode is based on the article Scientists Solve the Weird
Physics of How bats land Upside Down on House to
farks dot Com, written by Karen Kirkpatrick. Brainstuff is production
of I Heart Radio in partnership with hous towarks dot
Com and is produced by Tyler Plain. Four more podcasts
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