The Incredibly Weird Way Caterpillars React When You Yell Around Them

Don't scream, it's just a caterpillar!

The Incredibly Weird Way Caterpillars React When You Scream Around Them A3pfamily /

According to a video out of Canada, when you yell at caterpillars they react in a very strange way.

Of course, we are all bored out of our minds stuck at home in quarantine right now, so it's understandable for people to be looking for certain things to explore outside in nature. 

Especially if you have children, a good way to keep them entertained and teach them about the natural world around us is by taking them outside and exploring. 


When you have the time, you might as well use the chance to teach your kids something and get them away from being in front of the screens for a little while. 

Nature is an amazing thing and it's interesting the coping mechanisms that they use to protect themselves from predators and parasites. It's survival of the fittest and caterpillars, like every other species, evolve to survive. So, caterpillars do this head-bobbing technique when they hear specific frequencies. 

John Farley is a resident in Ontario, Canada, and he had a lot of tent caterpillars on his doorstep to his home. Farley saw some videos online that showcased caterpillars reacting to a human scream. So, when he noticed them on his doorstep, he decided to try a scientific experiment to see if caterpillars actually reacted that way when someone screams. 


Definitely, during these quarantines, people are looking for new ways of entertaining themselves. So, why not bother caterpillars in the name of science?

Farley found that when accosted by yells, the caterpillars would shake back and forth. 

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The Canadian Journal of Zoology affirms this strange reaction.


They write, "Western tent caterpillars respond to sounds of 300–2100 Hz by head flicking. The sound frequencies to which they are most sensitive match the flight sound of a fly parasite which lays eggs on the heads of caterpillars. Caterpillars on tents are more likely to head flick when stimulated by sound and have lower parasitization levels than fifth-instar caterpillars which have left the tent."

So, as a defense mechanism, they try to protect themselves even if it's a human making that noise because they cannot differentiate between the sounds of non-threatening human screams and threatening sounds made from flies flying. So, a scream triggers their automatic defense response. 

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Farley found out exactly what he wanted to know, that caterpillars do not like being screamed at. 

The caterpillars flail around and act in distress in the video.

Apparently, when the fly eggs that are deposited on the head of the caterpillar hatch, the maggots burrow into the caterpillar's body and feed off of it like a parasite and eventually kill the caterpillar. This chaotic action is the caterpillar's natural defense mechanism that could save their life from being overtaken by a parasite. 

So, if you were interested, this is why caterpillars react to certain sounds in a distressing way.

Interesting right? 


And I promise no caterpillars were harmed in the making of these videos. 

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Emily Francos is a writer who covers relationships, pop culture, and news topics.