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  • [♪ INTRO]

  • When it comes to synchronized swimming, nothing is more impressive than schooling fish

  • Hundreds or even thousands of them will choreograph their movements without a singular leader telling them what to do.

  • And you might think you know why: because schooling helps fish avoid being eaten

  • But that's only part of the story.

  • To really understand schooling, you don't just have to think about biology you also

  • have to dive deep into psychology and into physics.

  • There are technically two types of fish crowds: schools and shoals

  • Schools are highly coordinated groups that seem to move like a single organism,

  • while shoals are looser, less organized gatherings that can be huge, like the size of a city.

  • Still, despite their differences, both of these benefit fish beyond reducing the odds

  • they will disappear into a hungry mouth

  • You see, studies find that communal fish have lower metabolic rates than loners.

  • That means they use less energy going about their day to day lives, so they're healthier and have more stamina

  • In fact, researchers have found that fish living in groups have higher growth rates,

  • and their bodies are in better condition than isolated fish.

  • And that is where psychology and physics come into play

  • Scientists have long suspected that shoals and schools protect fish from predators because

  • it's helpful to have a lot of eyes scanning for danger

  • Plus, it can be difficult for predators to target individual fishes in a blurry mass of fins and tails

  • But it isn't just scientists who know there's safety in numbers.

  • The fish know it too

  • In 2016, researchers found that fish living in groups were calmer and less stressed than solo fish

  • And less stress means less energy spent stressing, so there's more available for things like growth and reproduction

  • But stress reduction isn't the only way schools help fish save energy.

  • There's also fluid dynamics.

  • When fish swim in schools, their endurance levels are two to six times greater than when they're traveling alone

  • So for many years, it was thought that it's easier for fish to swim in a school for the

  • same reason it's easier for birds to fly in a V formation

  • Essentially, the lead bird creates changes in air currents, so the other birds face less wind resistance.

  • But to create the same effect, fish would have to form specific patterns and maintain

  • certain distances from each other like birds do

  • And, I don't know if you've ever, like, watched fish before, but they don't do that

  • Problem is, it's really hard to measure flow patterns and energy use in wild fish.

  • So scientists couldn't figure out what actually goes on with them.

  • Then, for a 2020 study, scientists came up with a solution: robots.

  • The researchers made robots that look like carp, they put them in a tank, and measured

  • their swimming patterns more than 10,000 times

  • Based on this, they made predictions about how schooling fish optimize their speed and energy use.

  • Then, they tested those predictions on free-swimming goldfish

  • They found that by beating their tails out of sync with the fishes in front of them when

  • they're close, and matching their tailbeats when farther away,

  • these animals could capitalize on the small vortexes of moving water made by other fish

  • So, they save energy by constantly adjusting the rhythm of their tail beats and by chilling

  • out with a bunch of their best buds

  • And that means fish always benefit from schooling, even if there isn't a predator in sight

  • Thanks for asking! If you find yourself wondering about things like this a lot, I bet you'd enjoy other

  • Quick Question episodes, like Can Soda Save a Dying Fish?

  • So maybe watch that one next!

  • And you might consider clicking the subscribe button and ringing the notification bell.

  • That way, you catch every episode we make

  • [♪ OUTRO]


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B1 US fish schooling energy swimming save psychology

Why Do Fish School?

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    joey joey posted on 2021/05/05
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