< A new study finds peeing is contagious among chimpanzees

EMILY KWONG: You're listening to Short Wave from NPR.

REGINA BARBER: Hey, Short Wavers, Regina Barber here with science correspondent Jonathan Lambert. Welcome to the News Roundup.

JONATHAN LAMBERT: Thank you. Excited to be here on my first News Roundup with you all.

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.

ARI SHAPIRO: I only came because I heard you were going to be here, Jon.

[LAUGHTER]

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, Jon?

LAMBERT: Contagious peeing in chimps. Need I say any more?

SHAPIRO: No, please don't. [LAUGHS]

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

SHAPIRO: I love chirps and space.

LAMBERT: And better vegan cheese. We really contain multitudes.

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

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

SHAPIRO: Let's start with contagious peeing among chimps. Sorry, it's NPR-- we should say urination.

BARBER: Yes.

SHAPIRO: Contagious urination. What is going on?

LAMBERT: Yeah, OK, so to put this in context, have you ever heard of contagious yawning?

SHAPIRO: Yeah, totally.

LAMBERT: If I yawn, you get the urge to yawn, too?

SHAPIRO: Yes.

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

ENA ONISHI: 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.

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

LAMBERT: Yeah. So this observation got Ena 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.

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

LAMBERT: 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.

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.

SHAPIRO: Could she tell why this was happening?

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.

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

BARBER: Yeah.

SHAPIRO: Is that what you're telling me?

LAMBERT: 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.

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

LAMBERT: 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.

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.

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

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

SHAPIRO: Of course I do.

BARBER: Yeah.

[CHIRPING]

BARBER: Yeah, it's cool, right?

SHAPIRO: I feel like I'm in a jungle--

LAMBERT: Whoa.

SHAPIRO: --listening to the dawn chorus.

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

LAMBERT: 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.

RICHARD HORNE: 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.

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

SHAPIRO: How so?

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.

LAMBERT: 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.

SHAPIRO: 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?

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.

LAMBERT: 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.

SHAPIRO: Hmm. OK, should we make another really hard pivot from chorus waves in space to vegan cheese? What's up with the vegan cheese?

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?

SHAPIRO: 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.

BARBER: Of course.

LAMBERT: Hmm. 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.

SHAPIRO: So-- this is going to sound like the setup to a joke-- but how do you make better vegan cheese?

BARBER: Science, Ari. So Stacie Dobson is a PhD candidate at the University of Guelph in Ontario. And she and her research team developed this new cheese formulation and told us that the team's first step was to get a better understanding of 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.

LAMBERT: Specifically, a lot of plant-based cheeses and 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.

BARBER: Ooh.

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

BARBER: Yes, and Stacie 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.

LAMBERT: So, for example, Stacie 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.

SHAPIRO: Dare I ask how it tasted?

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--

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

LAMBERT: Stacie said the team was working 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.

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

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

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

LAMBERT: Always, yes.

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

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.

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

BARBER: Tyler Jones checked the facts. Ko Takasugi-Czernowin and Becky Brown were the audio engineers. I'm Regina Barber.

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

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