# eli5: How are squirrels able to survive a fall at terminal velocity?

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eli5: How are squirrels able to survive a fall at terminal velocity?

In: 6

Squirrels are small, light, and have fluffy bodies. This means their terminal velocity is quite slow and easily survivable no matter what height they fall from.

It’s around 23 mph btw

Here you go:
https://youtu.be/hFZFjoX2cGg

Edit: I can’t ELI5, but Mark Rober can.

It also has to do with how they essentially make atheir body a parachute, and turn/land at the last minute. Really interesting, actually.

Terminal velocity is decided by two things. The weight of something, and the surface it can expose to the wind. The higher the weight, the less wind will be able to offer resistance to it. The higher surface, the more wind will offer resistance.

Small critter gain speed slower because they’re much lighter. Fur and fluff also help increase the surface. With all those variables, things can find their terminal velocity. Different things have different terminal velocity. Animals and creatures that can spread their limbs to increase surface can thus reduce terminal velocity.

Finally, what decide whether we survive or not a fall? Simply put, when you hit the ground, all that movement energy you have turns against you. All that energy that cannot push you toward the ground instead hit you and can hurt you. Either by breaking limbs or rupturing organs. And those are necessary for our lives. The amount of energy you carry depends… On your weight (again). And that energy can be dispersed depending on how much surface hits the ground (again).

So why do squirrel survive terminal velocity? They are too light and have too much surface to go fast while falling. And when they hit the ground, their low weight, high surface and low speed mean that the shock does not produce enough force to cause lethal damages.

Another example of the universal ‘square-cube law’!

The mass of the small critter – and therefore the size of the force from gravity pulling them down – comes from the animal’s volume, which changes by their width times their length times their height – that is, three measurements multiplied together, which is something cubed.

The wind resistance that slows them down, acting against the force of gravity, changes by their length by their width – only two measurements multiplied together, which is something squared.

As the critter gets smaller, that mass and the force from gravity decreases a lot faster than the force from wind resistance. So small critters fall a lot more slowly.

Then when they land – The strength of their bones changes by the cross-sectional area of those bones, and the strength of the muscles by their cross sectional area. Those areas are the width of the bones and muscles squared. But again, the impact forces go down with the animals mass, which comes from volume, which is a measurement cubed. So their legs and bodies, compared with their size, are a lot stronger, and so can absorb these impact forces a lot more.

This square-cube law crops up everywhere. You’ll be surprised how often it drives things.

There might be a misunderstanding here, so I’ll try to clear it up. Aside from how squirrels survive their terminal velocity, let me clear up what terminal velocity is:

It is not a velocity which kills a thing (as in „terminally ill“).
It’s the max velocity something will reach in free fall.

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0

eli5: How are squirrels able to survive a fall at terminal velocity?

In: 6

Squirrels are small, light, and have fluffy bodies. This means their terminal velocity is quite slow and easily survivable no matter what height they fall from.

It’s around 23 mph btw

Here you go:
https://youtu.be/hFZFjoX2cGg

Edit: I can’t ELI5, but Mark Rober can.

It also has to do with how they essentially make atheir body a parachute, and turn/land at the last minute. Really interesting, actually.

Terminal velocity is decided by two things. The weight of something, and the surface it can expose to the wind. The higher the weight, the less wind will be able to offer resistance to it. The higher surface, the more wind will offer resistance.

Small critter gain speed slower because they’re much lighter. Fur and fluff also help increase the surface. With all those variables, things can find their terminal velocity. Different things have different terminal velocity. Animals and creatures that can spread their limbs to increase surface can thus reduce terminal velocity.

Finally, what decide whether we survive or not a fall? Simply put, when you hit the ground, all that movement energy you have turns against you. All that energy that cannot push you toward the ground instead hit you and can hurt you. Either by breaking limbs or rupturing organs. And those are necessary for our lives. The amount of energy you carry depends… On your weight (again). And that energy can be dispersed depending on how much surface hits the ground (again).

So why do squirrel survive terminal velocity? They are too light and have too much surface to go fast while falling. And when they hit the ground, their low weight, high surface and low speed mean that the shock does not produce enough force to cause lethal damages.

Another example of the universal ‘square-cube law’!

The mass of the small critter – and therefore the size of the force from gravity pulling them down – comes from the animal’s volume, which changes by their width times their length times their height – that is, three measurements multiplied together, which is something cubed.

The wind resistance that slows them down, acting against the force of gravity, changes by their length by their width – only two measurements multiplied together, which is something squared.

As the critter gets smaller, that mass and the force from gravity decreases a lot faster than the force from wind resistance. So small critters fall a lot more slowly.

Then when they land – The strength of their bones changes by the cross-sectional area of those bones, and the strength of the muscles by their cross sectional area. Those areas are the width of the bones and muscles squared. But again, the impact forces go down with the animals mass, which comes from volume, which is a measurement cubed. So their legs and bodies, compared with their size, are a lot stronger, and so can absorb these impact forces a lot more.

This square-cube law crops up everywhere. You’ll be surprised how often it drives things.

There might be a misunderstanding here, so I’ll try to clear it up. Aside from how squirrels survive their terminal velocity, let me clear up what terminal velocity is:

It is not a velocity which kills a thing (as in „terminally ill“).
It’s the max velocity something will reach in free fall.