The problem with modern avocados — and the ancient solution

Summary

Short Wave — "The Problem with Modern Avocados — and the Ancient Solution"
NPR, July 24, 2026
Hosts: Nate Rott, Hannah Chin
Guest: Elsa Chang (All Things Considered)

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Episode Overview

In this lively science news roundup, hosts Nate Rott and Hannah Chin are joined by Elsa Chang to explore three intriguing new scientific studies: the genetic history of avocados (and what it means for your guacamole), surprising discoveries about ancient Egyptian princesses, and the global intricacies of birdsong. The episode is packed with light humor, expert insights, and accessible explanations of cutting-edge research.

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Segment 1: The Trouble with Modern Avocados — and Genetic Diversity

Timestamps: 02:56–05:44

• The Hass Avocado Domination

  • Nearly all avocados sold commercially (over 80%) are of the Hass variety, prized for uniformity in flavor, size, and texture.

    "Because they're all genetically identical, they're all susceptible to diseases in the exact same way." — Nate Rott (03:16)

  • This genetic uniformity raises the risk of widespread crop failures if new diseases strike.

• What About Other Avocado Varieties?

  • Many wild and local avocado types exist—some are bigger, glossier, lighter green, and less fatty than Hass (03:44).
  • Kevin Wan, archaeobotanist at the Smithsonian and PhD candidate, went years studying avocados without ever tasting one!

    "I was gonna see if I could go my entire PhD studying avocados without ever having eaten one or eaten guacamole." — Kevin Wan (04:06)

• The Science: Mapping Avocado Genetics

  • Wan sequenced DNA from diverse avocados in Mexico and Central America, comparing samples much like an "Ancestry.com for avocados." (04:25)
  • Findings: Significant genetic diversity persists, including Nicaraguan avocados closely related to those in South America, indicating ancient farmers transported and hybridized them. (04:40)
  • Amber Vandewarker, anthropologist (UC Santa Barbara), underscores the importance of preserving this diversity for future sustainability (05:01).

• Did Kevin Wan Finally Taste an Avocado?

  • Yes, during fieldwork in Nicaragua, a farmer offered him one and, as Kevin laughs, "I couldn't say no."

    "You'll be happy to know that Kevin told me he eats avocados and guacamole almost every single day now." — Hannah Chin (05:35)

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Segment 2: Egyptian "Warrior" Princesses

Timestamps: 05:44–08:03

• A Surprising Basement Find

  • Egyptian Museum staff unearth a box containing the remains of a king and five princesses from ~1800 BCE, long forgotten in storage (05:57).

• Unexpected Weapons in Royal Graves

  • The princesses were buried with daggers, maces, bows, and arrows—weapons archaeologists traditionally associate with men (06:22).
  • At first, these were thought to be symbolic, given assumptions about "princesses" being delicate or ornamental.

    "We all have this assumption that princesses are like Disney characters, that they are fluffy, they—" — Zinab Hashish (07:00)
    "—are wearing beautiful dresses and very beautiful jewelry." — Elsa Chang (07:05)

• Strong Princesses, Strong Bones

  • Zinab Hashish, bioarchaeologist (Beni Suef University, Egypt), analyzed the bones.
  • Skeletons showed strong muscle attachments and bone curvature from repeated bow use.

    "These women were buff." — Elsa Chang (07:16)
    "Princess Nuphotep, her… right second hand bone shows a unique curve." — Hannah Chin (07:32)

  • While it’s unproven they fought as warriors, it's clear their lives were physically demanding and far from idle.

    "Their lives weren't as relaxed as we might have thought, that they did real work." — Nate Rott (07:42)

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Segment 3: The Universal Language of Birdsong

Timestamps: 08:03–10:16

• A Massive Song Study

  • Researchers analyzed over 116,000 birdsongs from perching birds (robins, thrushes, warblers, crows, etc.) worldwide (08:09).

• What Were Scientists Listening For?

  • Main question: How have the pitches and motifs of bird songs changed or converged globally? (08:23)
  • Despite immense variety, most birds use eight basic acoustic motifs to attract mates or defend territory (08:31).

• Birdsong in Action

  • Three Types of Trills:
    • Slow trill (Northern cardinal, Minneapolis) (08:45)
    • Ultra-fast trill (Bohemian waxwing, Newfoundland and Labrador)

      "Whoa… like a drill." — Elsa Chang (09:10)

  • All examples were crowdsourced from a global database of birders.

• Global Evolution of Motifs

  • Noted convergence: birds in dense, noisy forests have independently developed a loud, flat whistle motif for effective communication (09:30).
  • Lead author Quentin Piqueli:

    "Nature found the same solutions for the same constraints, but across different parts of the world." — Quentin Piqueli (09:59)

    • Birds “separated by oceans and continents all landed independently on the same types of acoustic patterns to communicate.” — Nate Rott (10:13)

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Notable Quotes & Memorable Moments

• "All puns considered." — Elsa Chang, on science podcast puns (01:31)
• On genetic diversity: "Avocados stay sustainable into the future." — Amber Vandewarker, paraphrased (05:01)
• On princesses: "Have these people not ever heard of Warrior Princess? Because women do carry weapons sometimes." — Elsa Chang (06:40)
• On birdsong: "It was almost like, I don't know, like a drill." — Elsa Chang (09:10)
• On convergent evolution: "That is so cool." — Elsa Chang (10:16)

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Episode Flow and Tone

The discussion is lively and approachable, peppered with friendly banter and puns—true to Short Wave’s relaxed, curious spirit. Elsa Chang’s reactions add extra enthusiasm, while the hosts keep the conversation brisk and information-dense, making the science both accessible and relevant to everyday life.

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Useful for Listeners Who Missed the Episode

This episode explores why genetic diversity in avocados matters for the future of food, challenges stereotypes about ancient women’s lives through anthropology, and reveals the surprisingly universal logic of birdsong, tying each study back to larger patterns in science and human history.

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End of Summary

Transcript

[Announcer]

This message comes from National Geographic's Pompeii out of Time with Tom Hiddleston. A new series from the executive producers of Loki. Pompeii out of Time with Tom Hiddleston is now streaming on Disney and Hulu.

[Nate Rott]

Hey, Nate Rodd here. Before we get into this episode, a quick ask for you to lift that finger and press the follow button on your app. We love telling you all the latest cool science out there. And following us helps you make sure that you never miss any new science stories coming from us and and have smarter, more informed conversations with all of your friends. We all want that, right? Okay, psa over here's the show.

[Announcer]

You're listening to Shortwave from npr.

[Nate Rott]

Hey, shortwavers. I'm still Nate Rott.

[Hannah Chin]

And I'm Hannah Chin with our bi

[Nate Rott]

weekly science news roundup featuring the one, the only, the exquisite Elsa Chang of All Things considered.

[Elsa Chang]

Neerat, you're very exquisite too. Thank you so much for having me again, guys.

[Nate Rott]

Happy you're here. Okay, so this week we've got a few discoveries that help us better understand this wacky world that we're all living in. The first is a discovery about ancient avocados, which are my favorite kind to eat. That could help us keep slathering our chips with guacamole today.

[Hannah Chin]

And the next one looks at the mummified remains of Egyptian princesses and upends some of our assumptions about how they lived.

[Nate Rott]

And the last study takes a global look at birdsong. Trust me, Hannah and Elsa, it's going to be trilling. Get it?

[Hannah Chin]

Yeah.

[Elsa Chang]

Puns.

[Nate Rott]

All puns considered. You're listening to Short Wave, the science podcast from npr.

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[Nate Rott]

All right, Hannah and Elsa, we've got a lot to get into.

[Hannah Chin]

Let's start with ancient avocados.

[Elsa Chang]

Is my avocado toast in danger here?

[Hannah Chin]

Well, not yet. So when you pick up avocados at the grocery store or when you get guac in your burrito, chances are that it's from a single type of avocado. It's called the Hass avocado.

[Elsa Chang]

Right.

[Hannah Chin]

And, Elsa, this type of avocado makes up more than 80% of commercial avocado

[Nate Rott]

production, which is, you know, kind of convenient because it means that our avocados tend to be, like, consistent in their size, shape, form, flavor wise. But because they're all genetically identical, they're all susceptible to diseases in the exact same way.

[Elsa Chang]

Oh, like farmers are putting all their eggs.

[Kevin Wan]

Haha.

[Elsa Chang]

Or avocados, shall we say, in one basket here. So are there other varieties of avocados that we could grow? So there's sort of, like, genetic variation?

[Hannah Chin]

Yeah, there are. And a lot of them look very different.

[Kevin Wan]

They're bigger, they're whiter, they're glossier, less bumpy, usually, like, lighter green, sometimes come in different shapes and sizes, and on the inside, they tend to be less fatty.

[Hannah Chin]

So this is archaeobotanist Kevin Wan. He's a fellow at the Smithsonian National Museum of Natural history and a PhD candidate at Texas A and M doing avocado research, even though up until a couple years ago, he'd never tasted one.

[Kevin Wan]

I was gonna see if I could go my entire PhD studying avocados without ever having eaten one or eaten guacamole.

[Nate Rott]

But what Kevin wanted to know was how much genetic diversity he was dealing with. So he collected DNA samples from a bunch of different avocado varieties in Mexico, Central America, mostly from local farmers or home gardens.

[Hannah Chin]

Yeah, and he sequenced the genomes of these avocados to compare them to each other and also to an existing archive of avocado varieties. Kind of like a 23andMe or Ancestry.com test, but for avocados.

[Elsa Chang]

That's kind of cute. Okay, so what did they find?

[Nate Rott]

So he found a lot of genetic diversity and a few varieties of Nicaraguan avocados that were super genetically similar to those in South America, which suggests they were brought there by ancient farmers and then hybridized with native speed. Kevin published a paper on these findings this past week in the scientific journal Plants, People Planet.

[Hannah Chin]

And I talked to anthropologist Amber Vandewarker. She's at UC Santa Barbara. And she wasn't involved with the study, but she said Kevin's research really reveals this genetic diversity that has been preserved over the past thousands of years by these intrepid ancient farmers. And she told me it's important for us to keep this diversity alive. Right. So avocados stay sustainable into the future.

[Elsa Chang]

Totally. But I am still dying to know, did Kevin ever eat an avocado?

[Hannah Chin]

He did.

[Kevin Wan]

When I was interviewing that farmer in Nicaragua, he picked off one of the avocado foods and said, here, try this. And I couldn't say no.

[Elsa Chang]

No, you couldn't.

[Hannah Chin]

Exactly. And, Elsa, you'll be happy to know that Kevin told me he eats avocados and guacamole almost every single day now.

[Elsa Chang]

Good for him.

[Nate Rott]

Good man.

[Elsa Chang]

So let's move on to Egyptian princesses. Tell me more.

[Hannah Chin]

Yeah. So maybe what I love most about the story is that it came from an effort to unclutter a basement.

[Nate Rott]

Yeah. So that's what the Egyptian Museum in Cairo was doing when they rediscovered this box with the mummified remains of six members of an ancient Egyptian royal family that had been excavated and stashed more than 100 years ago.

[Elsa Chang]

Yeah, totally normal thing to find in one's basement, of course. So who was this family?

[Hannah Chin]

It was five princesses and a king who lived thousands of years ago around 1800 B.C.

[Elsa Chang]

wow. A girl, dad.

[Hannah Chin]

Yeah, exactly.

[Nate Rott]

Yeah. But one of the things that confused the archaeologists when they found these remains was that the women were all buried with weapons like daggers and maces and bows and arrows, which archaeologists typically associate with men, of course. So the assumption was the princesses were buried with these weapons for symbolic reasons.

[Elsa Chang]

Symbolic. Wait, hello. Have these people not ever heard of Warrior Princess? Because women do carry weapons sometimes.

[Hannah Chin]

Okay, Exactly. And that's what the person who helped find these remains wanted to figure out.

[Nate Rott]

Yeah. Her name is Zinab Hashish. She's a bioarchaeologist at Beni Suef University in Egypt. And she says, you know, we all have this assumption that princesses are like

[Hannah Chin]

Disney characters, that they are fluffy, they

[Elsa Chang]

are wearing beautiful dresses and very beautiful jewelry.

[Hannah Chin]

When Zaynab looked at these bones, she noticed that these skeletons had really strong muscle attachments.

[Elsa Chang]

These women were buff.

[Hannah Chin]

Exactly. And she did a deeper analysis of the bones, and she found these women were. Yeah, buff. They were really strong. Strong for arms and shoulder. And also, for example, Princess Nuphotep, her Right. Second hand bone shows a unique curve.

[Nate Rott]

And that curve, Elsa, likely came from the repeated use of a bow and arrow. Wow.

[Elsa Chang]

Wait, so these women literally were warrior princesses?

[Nate Rott]

Well, Zeynep says it's unclear if these findings, which were published in the journal Frontiers in Environmental Archeology, proved that they were actually like warriors in the sense that they fought. That's also what I heard from another Egyptologist who wasn't involved in the study. But he says it does show that their lives weren't as relaxed as we might have thought, that they did real work.

[Elsa Chang]

They were shooting bows and arrows. All right, our final topic is birdsong. What are you going to tell me about singing birds?

[Nate Rott]

Yeah. So this study analyzed more than 116,000 bird songs from perching birds, which include, you know, robins and thrushes, warblers and crows, and on and on.

[Elsa Chang]

Cool. Okay, so what were the scientists looking for specifically in all of these bird songs?

[Nate Rott]

Yeah, so they were listening for how the pitch of songs were changing over time to try to find patterns. Acoustic motifs is the technical term.

[Hannah Chin]

And they found that for all the variety there is in these birds worldwide, they're all trying to communicate basically one of two. Either attracting mates or claiming territory. And they use these eight basic motifs.

[Elsa Chang]

Okay, so what are the eight different motifs?

[Nate Rott]

So there are three different types of trills. There's a slow trill sung here by a northern cardinal recorded outside of Minneapolis,

[Hannah Chin]

And an ultra fast trill.

[Elsa Chang]

Whoa, was that the ultra fast I just did?

[Nate Rott]

Ultra fast?

[Hannah Chin]

Yeah. And that one's sung by a bohemian waxwing in the Canadian province of Newfoundland and Labrador.

[Elsa Chang]

That's amazing. It was almost like, I don't know, like a drill.

[Nate Rott]

The most appropriate use of the word ultra you can imagine. Yeah, and it's worth noting that all these recordings were collected from a public database where birders uploaded songs, and we

[Hannah Chin]

don't have time to cover all eight of them. But another pattern that's maybe worth knowing is the flat whistle

[Nate Rott]

that sung by a three wattle bellbird in Costa Rica. And the reason it's worth knowing that call is the researchers on this new study found that in the dense, loud tropical forests all over the world, birds have independently evolved this type of call.

[Elsa Chang]

Wait, so that flat whistle call, does that give them some kind of advantage?

[Hannah Chin]

Well, it's simple and it's loud, so it can be heard in a wide area. Here's the lead author of this study, Quentin Piqueli. He's a PhD candidate studying bioacoustics in Paris.

[Nate Rott]

So that's really impressive to see that nature found the same solutions for the same constraints, but across different parts of the world. So in other words, Elsa birds separated by oceans and continents all landed independently on the same types of acoustic patterns to communicate.

[Elsa Chang]

That is so cool.

[Nate Rott]

Well, Elsa, thank you so much for geeking out with us this week. Come back anytime.

[Elsa Chang]

Always. It's so fun to hang with you guys.

[Nate Rott]

You can hear more of Elsa Cheng on consider this NPR's afternoon podcast about what the news means for you.

[Hannah Chin]

And for more science stories just like this one, follow Short Wave on whatever app you're listening to.

[Nate Rott]

This episode was Produced by Burley McCoy and Jordan Marie Smith. It was edited by Lauren Gonzalez, Rebecca Ramirez and Christopher Intagliata.

[Hannah Chin]

Tyler Jones Check the facts. Anley Wong, Robert Rodriguez and Peter Elena were the audio engineers. I'm Hannah Chin.

[Nate Rott]

And I'm Nate Rott. Thanks for listening to Shortwave, the science podcast from npr.

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