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Comment by jajko | Hacker News Reader

Its interesting how unskilled nature can be and still get away with it (here I guess to the thick fur/skin/fat below).

If humans would jump from such height so badly, many injuries and possibly few deaths would be happening. I've done my fair of jumps in Swiss swimming pools / beaches where 10m jumping board is standard equipment, and even slightly incorrect landing can be quite brutal on the body. Falling ie on the back badly orientated could easily move vertebrae with corresponding consequences.

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It's mainly due to the square/cube law. Small things, including animals, can fall from great heights with little damage.

Add feathers to that, and those heights become really great.

Or, as Haldane wrote in “On being the right size” (https://en.wikipedia.org/wiki/On_Being_the_Right_Size:

“You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom, it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes. For the resistance presented to movement by the air is proportional to the surface of the moving object. Divide an animal’s length, breadth, and height each by ten; its weight is reduced to a thousandth, but its surface only to a hundredth. So the resistance to falling in the case of the small animal is relatively ten times greater than the driving force”

That’s half the equation and explains why speeds are lower.

There’s another square cube relationship around the volume of an object vs the impact area.

And tensile strength of muscles and bones, which is proportional to cross-section area, hence also is tenfold stronger relative to mass.

I'd imagine that jumping so far into such cold water, even if your form is perfect, would also be quite shocking to your system and probably dangerous in and of itself. I say this as someone who went swimming with penguins in Antarctica this January. No way I would enter that cold water so deeply and quickly.

Evolution is big on expending the minimum amount of resources to achieve the can-get-away-with-it level.

Indeed. Not to mention, aside from a few "jumps", most of the falls in the video seem unwanted/slips due to pushing. Uncoordinated, and hitting the water pretty much randomly.

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