How does an immortal jellyfish go back to being a baby?
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Moment of Um comes to you from APM Studios. I'm Anna Goldfield. When I was a kid, I spent a lot of time wondering what it would be like to be a grown-up. Seemed pretty cool at the time. There'd be nobody telling me when to go to bed. I could eat any fun snack I wanted. I could drive a car and go wherever my heart desired. But you know what I didn't really think about? That being a grown-up is complicated.

There are bills, jobs, groceries, laundry, taxes. Sure, there are lots of wonderful parts, but sometimes I really, really wish I could be a kid again. A baby, even. Just a cute, squishy little baby, eating, napping, playing, not knowing anything about bills or taxes or laundry. But, alas, I can't grow back into a baby.

Did you know there is one kind of animal that can do exactly that? Mm-hmm. The immortal jellyfish. What's their secret? My friend Braxton was wondering this too, so I found an expert to tell us all about it. There is only one species that I'm aware of that is the immortal jellyfish. And it has earned its nickname as the immortal jellyfish for an extremely good reason.

My name is Christina Couch. I am a writer and I write about brains, behaviors, and bizarre animals for the most part. I love science. I love talking about science. And I've written a book for kids ages 9 through 12. It's called Innovative Octopuses, Half-Brain Birds, and More Animals with Magnificent Minds. So...

Whenever this jellyfish is hurt or encounters really bad conditions under the ocean, basically it sucks its tentacles in and then behaves like a baby. They're not just being tucked in, they're being absorbed into the body. It would be a little bit like

if you broke a bone or something and then just sucked that back into your body and re-grew it. So it pulls its tentacles in if it gets really hurt, and then it sinks to the bottom of the sea or to like the nearest hard place.

It attaches itself there, and then it pretty much just starts its life over again, which is really wild. Other jellyfish do not do this. This is an extremely rare thing. So the way that it sort of starts over is it essentially, it sprouts a stalk called a polyp, and it basically like clones itself. And so the stalk grows bigger and bigger. It

eventually blooms just like in the exact same way of when this jellyfish was a newborn, an actual newborn. And then it starts releasing new jellyfish. And when you look at the new jellyfish that are coming out, they are identical scientifically to the old one. And this jellyfish can do it again and again. So we actually don't really know how old these things live because they can just kind of keep regenerating themselves.

That doesn't mean that they just never die. That is not true. These jellyfish can be hurt, they can be eaten, they can encounter all sorts of things that end their lifespan. But we don't really know the limits to how many times they can regenerate. Whoa. I never thought I'd be jealous of a jellyfish. But here we are.

The immortal jellyfish can respond to getting hurt or stressed out by finding a place to rest, absorbing its own tentacles, and regrowing into a baby version of itself. And not just one self-baby, they make clones of themselves too. That is so cool. Well, I can't do that. But at least if I'm stressed or sad, I can take care of myself by napping, eating snacks, and hanging out in my cozy pajamas.

Just like a baby. A baby who can order a pizza. If you like this episode, take a second to subscribe to Moment of Um wherever you listen to podcasts. And if you want to learn more about beautiful blobby jellyfish, check out the Brains On podcast where we have a whole episode all about what's inside their squishy bodies. Want to see our shows come to life?

Head to YouTube, where we've got awesome animated Brains On episodes. Search Brains On Universe on YouTube and subscribe. If you have a question, we'd love to help you answer it. Drop us a line by going to brainson.org slash contact.

Moment of Um is produced by Molly Bloom, Rachel Brees, Rosie DuPont, Anna Goldfield, Ruby Guthrie, Mark Sanchez, Anna Weigel, Nico Gonzalez-Whistler, and Aron Moldeslassie. We had editing help from Shayla Farzan and Sandin Totten, and engineering help from Alex Simpson. Our theme song is by Mark Sanchez. Our executive producer is Beth Perlman. The executives in charge of APM Studios are Chandra Kavati and Joanne Griffith.

Special thanks this week go to Liz Farhat, Christine Solomon, and Christina Couch. See you next time, and the next day, and every weekday. Until then... Yeah, hi, could I get a medium cheesy deluxe pizza with extra cheese? Awesome. Thank you so much. Bye.