Yesterday, I wrote a piece about mantis shrimps and their ridiculous belligerence, pointing out their record-breaking, shell/glass-smashing punches. A reader replied:
It is actually collapse of cavitation bubbles that does the damage, not the strike itself. They also have the best eyes in the world: 16 photoreceptors to 2 that humans possess.
Indeed, the mantis shrimp’s “fist” moves so quickly that it creates a wave of low pressure in front of it, and small bubbles. These bubbles release an enormous amount of energy when they collapse and this process, known as cavitation, is incredibly destructive. But so is being hit by a club moving at 51 miles per hour and reaching accelerations over 10,000 times that of gravity. That shit will hurt. And it’s the fact that the club moves so fast that causes the cavitation in the first place.
More importantly, the thing with the eyes mentioned by the reader is one of the most persistent myths about mantis shrimps, popularised by a delightful but sadly wrong Oatmeal cartoon.
It’s true that some species have 16 cone photoreceptors compared to our 3. People commonly take that to mean that they must see many more colours than we can or, as the Oatmeal put it:
Alas, no. Mantis shrimps turn out to be terrible at colour discrimination. In terms of telling two similar colours apart, they’re much worse than us, and pretty much anything else that’s been tested—see this old post of mine for more. Their eyes are extraordinary but probably because they deal with colour in a very different way than ours.
And formidable though they might be, mantis shrimps are no match for the acid-spewing disco clam ...