Peeing Is Contagious!

At least, it's contagious among a group of captive chimpanzees at the Kumamoto Sanctuary. How do researchers know? A very dedicated grad student at Kyoto University. In the quest for scientific knowledge, Ena Onishi https://www.google.com/url?q=https://www.wrc.kyoto-u.ac.jp/en/members/onishiE.html&sa=D&source=docs&ust=1737660944152626&usg=AOvVaw3fiMRBCQnfLZrWwtcDaSrY logged over 600 hours in the field! This episode, host Regina G. Barber https://www.npr.org/people/1082526815/regina-g-barber and special guests Jonathan Lambert and Ari Shapiro get into the nitty gritty of the research and their hypotheses for why this is happening in this episode. Read Jonathan's full reporting https://www.npr.org/2025/01/22/nx-s1-5262906/peeing-is-contagious-in-chimpanzees-study-suggests about contagious peeing in chimps. Delighted by other scientific discoveries you think we should share with the whole class (the rest of our audience)? Let us know by emailing [email protected] mailto:[email protected]! Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave. See pcm.adswizz.com https://pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences. NPR Privacy Policy https://www.npr.org/about-npr/179878450/privacy-policy

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• 0:18Regina Barber?

  You're listening to Short Wave from NPR.

• 0:23Regina Barber?

  Hey, Short Wavers. Regina Barber here with science correspondent Jonathan Lambert. Welcome to the news roundup.

• 0:27Speaker 02

  Thank you. Excited to be here on my first news roundup with y'all.

• 0:30Regina Barber?

  We are totally excited to have you. And we're also excited to have a news roundup favorite, Ari Shapiro, one of the hosts of All Things Considered. Welcome back.

• 0:38Speaker 03

  I only came because I heard you were going to be here, John.

• 0:42Regina Barber?

  OK, so we're going to do what we usually do. We're going to go over three science stories in the news. The first one being what, John?

• 0:49Speaker 02

  Contagious peeing in chimps. Need I say anymore?

• 0:53Speaker 03

  No, please don't.

• 0:55Regina Barber?

  And not only do we have peeing chimps, but we're also going to get chirping course waves from space.

• 1:01Speaker 03

  I love chirps and space.

• 1:03Speaker 02

  And better vegan cheese. We really contain multitudes.

• 1:07Regina Barber?

  We totally do. All that on this episode of Short Wave, the science podcast from NPR.

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• 2:34Regina Barber?

  OK, Ari, where do you want to start today?

• 2:37Speaker 03

  Let's start with contagious peeing among chimps. Sorry, it's NPR. We should say urination.

• 2:43Regina Barber?

  Yes.

• 2:43Speaker 03

  Contagious urination. What is going on?

• 2:46Speaker 02

  Yeah, OK. So to put this in context, have you ever heard of contagious yawning?

• 2:50Speaker 03

  Yeah, totally.

• 2:51Speaker 02

  Like, if I yawn, you get the urge to yawn too?

• 2:53Speaker 03

  Yes.

• 2:53Regina Barber?

  Yeah, I'm holding back the yawn right now. So Ina Onishi, a grad student at Kyoto University in Japan, was studying a group of captive chimpanzees when something similar struck her as odd.

• 3:03Speaker 05

  I noticed that they seemed to have a tendency to urinate around the same time. And it kind of reminded me of some human behaviors of going to the bathroom together, for example.

• 3:14Speaker 03

  So like, the same effect is making chimps pee together that makes us yawn in sequence?

• 3:20Speaker 02

  Yeah. So this this observation got Ina wondering if this behavior might be socially contagious, like yawning. And to see if it was, she spent more than 600 hours watching a group of 20 chimpanzees.

• 3:32Speaker 03

  To see when they pee? She had to track every time one of them relieved themselves?

• 3:35Speaker 02

  Yeah. And she said that it was easier to hear them pee than to see them pee. But so she noted when each individual chimp peed and where they were relative to each other. And looking at the data altogether, an interesting pattern emerged.

• 3:48Regina Barber?

  So basically, chimps were peeing together a bit more often than you'd expect if they were just peeing at random. And she published that conclusion in the journal Current Biology this week.

• 3:57Speaker 03

  Could she tell why this was happening?

• 3:58Regina Barber?

  So being closer helped, but proximity wasn't like the main factor here. Chimps have a hierarchical society. And it turns out that the lower-ranking chimps were more likely to catch the urge to pee from more dominant chimps.

• 4:10Speaker 03

  So when my boss pees, I'm going to pee?

• 4:12Regina Barber?

  Yeah.

• 4:12Speaker 03

  Is that what you're telling me?

• 4:13Speaker 02

  Maybe. And they don't know why this is. It could just be that lower-ranking chimps are paying closer attention to higher-ranking ones. But that's just one possibility.

• 4:21Speaker 03

  OK, so there's clearly more to study here. But is there any evolutionary reason that contagious urination would be an advantage?

• 4:29Speaker 02

  One idea is that doing the same thing together just kind of helps a group sync up, which could help them operate better as a unit. If this happens in the wild, it might help the chimps avoid predators who get attracted by the smell of pee by concentrating it all in one spot.

• 4:44Regina Barber?

  But we can't rule out that there might be like a non-adaptive reason. It could be just that the chimps pee when they hear other chimps pee. Sort of like humans get the urge when you hear like running water.

• 4:55Speaker 03

  OK, let's move on from that one. Tell me about our second story, a chorus in space.

• 5:02Regina Barber?

  Yeah, so there are these things called chorus waves. Do you want to hear?

• 5:04Speaker 03

  Of course I do.

• 5:05Regina Barber?

  Yeah.

• 5:09Regina Barber?

  It's cool, right?

• 5:10Speaker 03

  I feel like I'm in a jungle listening to the dawn chorus.

• 5:12Regina Barber?

  Yeah, it's an audio clip and it's been reconstructed from radiation coming 100,000 miles above Earth's surface.

• 5:19Speaker 02

  That's about 165,000 kilometers. It's a natural phenomenon thought to be created from bunched up electrons trapped in Earth's magnetic field. And what's interesting is that these waves have been studied for almost 70 years, but Earth's chorus waves have never been found that far out until this recent study published in Nature.

• 5:36Speaker 06

  But the surprising thing is they actually observe it and they see these waves in this region, which is kind of unexpected. It changes our ideas a little bit.

• 5:43Regina Barber?

  So that's Richard Horn, a professor and distinguished research scientist at the British Antarctic Survey on Space Weather. He wasn't part of the study, but he said the study might change how scientists think chorus waves are created.

• 5:53Speaker 03

  How so?

• 5:54Regina Barber?

  Well, the leading hypothesis on how chorus waves are created suggests that gradients in the Earth's magnetic field are very important and that as chorus waves grow, they should cause bunching of electrons.

• 6:05Speaker 02

  But here's the complication. This study, for the first time, found chorus waves further out, where Earth's magnetic field is much weaker and non-uniform. And yet, the waves were growing and the electrons were still bunched, so the magnetic field gradient did not seem to be that important.

• 6:20Speaker 03

  I'm sure Brian Eno is going to make a record with these waves any day now, but if I'm not Brian Eno, why should I care about this?

• 6:26Regina Barber?

  Right, I mean, legit question. Electrons create these waves and then the waves themselves affect the electrons. It's like a feedback loop. Chorus waves can actually like push these electrons to move nearly the speed of light.

• 6:38Speaker 02

  And these extremely fast particles can disrupt electrical components that are aboard so many communication satellites and can damage spacecraft, too. So understanding how chorus waves are created is important to our everyday lives.

• 6:51Speaker 03

  Hmm, OK, so we make another really hard pivot from chorus Waves in space to vegan cheese? What's up with the vegan cheese?

• 6:57Regina Barber?

  Yeah, so I'm lactose intolerant. I'm not a fan of vegan cheese, but I'm like excited for possible better vegan cheese in the future. So my question to you, have you tried it?

• 7:06Speaker 03

  Oh, I spend a lot of time with vegans. I've absolutely tried vegan cheese. I think they do better at like the ultra-processed Velveeta-type stuff than they do at like the artisanal aged cheddar.

• 7:15Regina Barber?

  Of course.

• 7:16Speaker 02

  Well, regardless of how you two feel, it definitely fills a niche. But many of these cheese alternatives you can buy in stores are also lower in protein than dairy cheese and use a lot of starch. And they often just don't melt and stretch like real cheese.

• 7:29Speaker 03

  So this is gonna sound like the setup to a joke, but how do you make better vegan cheese?

• 7:34Regina Barber?

  Science, Ari. So Stacy Dobson is a PhD candidate at the University of Guelph in Ontario. And she and a research team developed this new cheese formulation and told us that the team's first step was to get a better understanding on how the protein starches and fats were like all working together. They looked at a bunch of proteins, including lentils and fava beans and pea protein, and they tested those with different fats.

• 7:56Speaker 02

  Specifically, a lot of plant-based cheeses in stores use coconut oil. But researchers found if they blended coconut oil with sunflower oil, their cheese melted and stretched even more like dairy cheese.

• 8:07Speaker 03

  You gotta have that melty stretch in a grilled cheese sandwich.

• 8:10Regina Barber?

  Yes. And Stacy says that the team also put these combinations into a machine that's kind of like a CT scan, but for food. So it lets the researchers look at the inside of the structures, things like how big the fat globs were inside each version of the cheese.

• 8:24Speaker 02

  So for example, Stacy saw that big oil globules kind of spread out more in the mouth and could work well for things that need to be melty, like grilled cheese. They wrote all about it in the journal Physics of Fluids.

• 8:36Speaker 03

  Dare I ask how it tasted?

• 8:38Regina Barber?

  Yeah, so she and her team said that they tried like lots of this cheese during the research process. They had this little pizza oven and toaster to test it all out. And she says.

• 8:48Speaker 00

  If I made you a grilled cheese sandwich with it, you wouldn't be able to tell the difference between that and dairy cheese.

• 8:53Speaker 02

  Stacy said the team was working only on some aspects of these cheeses. And there's a lot of work the industry still needs to do to figure out even better ways to make them act and taste like dairy cheese.

• 9:03Regina Barber?

  Ari, we missed your energy. We're so happy to have you back. Thank you for coming and hanging out with us.

• 9:08Speaker 03

  I'm not gonna say I wanted a break from politics, but now that I've been here with you all, I think maybe I needed it.

• 9:13Regina Barber?

  Yeah, some science news is always good for the soul.

• 9:15Speaker 03

  Always.

• 9:18Speaker 02

  You can hear more of Ari on Consider This, NPR's afternoon podcast about what the news means for you.

• 9:23Regina Barber?

  And before we go, we want to say a big thank you if you're one of the listeners who answered the call in the last few months and supported our show by signing up for NPR+. That support is so important to keeping our week going. So, thank you. And if you've heard about NPR+, but you haven't supported us yet, it's really easy to sign up. Just go to plus.npr.org.

• 9:42Speaker 02

  This episode was produced by Hannah Chin and Jordan Marie Smith. It was edited by Rebecca Ramirez and Christopher Intagliata. Rachel Carlson contributed reporting.

• 9:51Regina Barber?

  Tyler Jones checked the facts. Co-Takasuki Chernovin and Becky Brown were the audio engineers. I'm Regina Barber.

• 9:57Speaker 02

  And I'm Jonathan Lambert. Thanks for listening to Short Wave, the science podcast from NPR.

• 10:05Speaker 00

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