IRA FLATOW: This is Science Friday. I’m Ira Flatow. A little later in the hour, we’ll tease apart what’s fact and what’s fiction in HBO’S new fungI-filled series The Last of Us.

SPEAKER: Any one of them could become capable of burrowing into our brains and taking control not of millions of us but billions of us. Billions of puppets with poisoned minds, permanently fixed on one unifying goal– to spread the infection to every last human alive by any means necessary.

IRA FLATOW: Plus, thinking about new technology for small modular nuclear reactors. But first, speaking of energy, there’s a milestone in renewable energy. For the first time, wind and solar generated more energy in the European Union than any other source of power.

Joining me now to talk about this and other top science stories of the week is Roxanne Khamsi, science writer based in Montreal. Roxanne, welcome back to Science Friday.

ROXANNE KHAMSI: Thank you so much, Ira. I am energized to be here.

IRA FLATOW: I can tell. Let’s make use of that. Let’s talk about what’s going on in the EU. Who would have thunk years ago more energy generated by wind and solar?

ROXANNE KHAMSI: Yeah. I mean, I could barely believe it when I read this news. But apparently, according to this think tank called Ember, there’s been this massive shift where now, as of 2022, last year, wind and solar overtook these other forms of energy sources. And the reasons that that happened are really interesting. But it’s really a landmark moment if you think about how far we’ve come in terms of renewables.

IRA FLATOW: And the reason why it happened, what was the catalyst, as we say in science?

ROXANNE KHAMSI: Well, so they point to three factors, which I find fascinating that it’s so multifactorial. One of them is the war in Ukraine, which obviously has created all sorts of disruptions to the flow of energy from places like Russia. And another reason is that there was a massive drought, and so there was less energy coming from hydro, which has historically produced a bunch of energy.

And then kind of related to that, the weather has been a little bit milder, so there was less of a demand for energy. So these three forces kind of combined to create this environment where wind and solar now have taken the forefront.

IRA FLATOW: I would imagine that we’re seeing the same pattern taking place in the US.

ROXANNE KHAMSI: We are, except it’s slightly different. So over in Europe now, wind and solar account for a fifth. And if you want to do the math, that’s 20% of all energy. In the US, the situation is slightly different where wind and solar account for 13% of energy sources. And that’s changing, but it’s not quite there yet at the 20% that Europe’s seen.

IRA FLATOW: Mm-hmm. All right, let’s move on to something that we here on Science Friday have been following for quite some time but with a new twist, and I’m talking about a study showing that older strains of the coronavirus are still circulating in the white-tailed deer long after they have disappeared in humans. Tell us about that.

ROXANNE KHAMSI: Yeah, so we’ve talked a lot about the animal reservoirs of coronavirus because coronavirus is not just something that humans get affected by. It’s something that a lot of different animals do. And one of those animals is the white-tailed deer. And what the researchers did was they looked at samples from hunting, about 5,000 tissue samples from the hunting seasons of 2020 and 2021, and they saw that there was a jump, first of all, in the number of samples that tested positive for coronavirus.

So it went from less than 1% to 21% of samples testing positive for coronavirus. And they found that humans, we’d seen waves of alpha and gamma but then we’d moved on to delta, unfortunately, because, of course, delta wasn’t great, but in the deer population, the alpha and gamma just hung around for a while. And so that’s fascinating in terms of implications for us and the deer.

IRA FLATOW: Oh, dear me, what about the deer? Could all these old coronaviruses be actually harming them?

ROXANNE KHAMSI: Yeah. Well, so that is a real concern that somehow– as you know, coronaviruses had this propensity to mix and match, so alpha and gamma and delta– there might be an opportunity for them to recombine and form some other kind of version of coronavirus that might not be as good for the deer or might not be as good for us. So we’re keeping an eye on this long tail, if you will, of coronaviruses in animal reservoirs like the deer.

IRA FLATOW: Let’s move on through the animal kingdom. I know your next story is about quolls, an animal that’s willing to skip sleep in favor of sex but to the extreme.

ROXANNE KHAMSI: Yes.

IRA FLATOW: Let’s back up a bit, and tell us what a quoll is for those of us uninitiated.

ROXANNE KHAMSI: It’s a golden-hued, cat-sized marsupial that lives in Australia with these cute little white spots. And as you say, it’s kind of going the distance, if you will, for sex, but at a great cost.

IRA FLATOW: What do you mean? What did the researchers find?

ROXANNE KHAMSI: So they found that some of these male quolls were traveling more than six miles in a night, which for a human is like 24 miles– so imagine walking 24 miles to get busy, if you will– and then what kind of toll that would put on these male quolls that are making that journey. So they’re living about a year, whereas the females are living about four years. And in a population that’s endangered, the researchers are finding that that journey is actually costing the males a huge amount.

IRA FLATOW: So they’re dying from exhaustion is what you’re saying?

ROXANNE KHAMSI: They’re dying from exhaustion. As they’re exhausted, the parasites are more likely to latch on to them and cause havoc for them. They’re just going too far, if you will, and they’re paying the price.

IRA FLATOW: They’re paying the price. But haven’t they always behaved this way? Is there something new here that the scientists have discovered?

ROXANNE KHAMSI: Well, as you might imagine, the habitats that these animals are living in are becoming more fragmented, so they do have to travel longer distances. So that’s a speculation in terms of one factor that’s kind of super charging, if you will, the cost of these long journeys.

IRA FLATOW: Yeah. Let’s go on to another story, and this one is connected to Neanderthals. And I like the story because it turns out that Neanderthals, we think we know so much about them, but we constantly discovering new stuff about how they lived. And this one is about Neanderthals traveling in big enough groups to kill and eat giant elephants.

ROXANNE KHAMSI: Yeah.

IRA FLATOW: Wow.

ROXANNE KHAMSI: Neanderthals like to party, apparently, big time, having raves.

IRA FLATOW: What’s going on there?

ROXANNE KHAMSI: So this was super interesting because these bones have been around as long as I have. They’ve been around since the 1980s. And what researchers did is they took a fresh look at them, and they said, what are these signs of butchery? When you butcher something, sometimes that thing that you’re– the tool you’re using will hit the bone and leave a mark.

And they looked at the mark of these giant elephants that are now extinct, but imagine straight-toothed giant elephants roaming thousands and thousands of years ago. The amount of meat on that elephant would feed about 400 people or 400 Neanderthals, if you imagine they’ve got appetites similar to ours. And yet they got every ounce of meat off of that elephant. So clearly, they weren’t just taking a chunk and leaving it because we used to think that they would just travel in small groups. This suggests that perhaps there were hundreds of them gathering at a time.

IRA FLATOW: I can imagine that they– yeah, they must coordinate and have maybe a group and then they go out hunting together.

ROXANNE KHAMSI: It could be. It could be. I mean, if only we had a time machine to go back in time and see.

IRA FLATOW: Well, how does this change our understanding then of how Neanderthals lived? I mean, they lived in much bigger groups than we thought?

ROXANNE KHAMSI: That is exactly what it is challenging. It’s challenging this thought that we had that they were always going in small groups. Now, I mean, hundreds of them, potentially, gathering around this feast really upends, to some degree, our thinking about who Neanderthals were, how they behaved, all that stuff.

IRA FLATOW: I love this stuff. OK, let’s continue on the theme about the importance of community. Researchers recently published a study showing that mammals who live in groups tend to live longer than ones who live alone. Please tell us more about that one.

ROXANNE KHAMSI: So this particular story for me really hit home because we’ve been talking a lot about isolation during this pandemic. And what the researchers found is they looked at more than 900 different mammal groups, or types of mammals, and they found that those that live in groups, those that are social animals, if you will, tend to live longer than those that tend to be more solitary.

So your elephants that like to be in groups with highly complex social structures live longer than tigers. And actually, the naked mole rat really shines because it lives for 31 years. And whereas other animals similar to it live less long, naked mole rats, of course, have these extremely complex social structures to make up for, frankly, in my opinion, not looking so great, being all hairless and stuff.

IRA FLATOW: How long do they live, naked mole rats?

ROXANNE KHAMSI: They live 31 years. So–

IRA FLATOW: Wow.

ROXANNE KHAMSI: –they live an extremely long time. And to the calculus of these researchers, that really underscores the idea that something about group living is helping mammals live longer than those that don’t.

IRA FLATOW: Is it the same for people, do you think?

ROXANNE KHAMSI: Well, there are some studies in baboons that suggest that more social baboons live longer than other baboons in the group that aren’t as social. We do know that having social ties does help people in old age live healthier and longer. So there’s something about living together, perhaps it’s the protection of the herd, perhaps it’s the stimulus of being together, that helps us extend our life.

IRA FLATOW: All right. Let’s wrap up this with a story about mummies. See what I did there? OK. Researchers have uncovered the recipe for mummification. So what’s in a mummy that mummifies?

ROXANNE KHAMSI: So for a long time, what scientists had to do was look at the mummies themselves, and also ancient texts, to try to understand the process of mummification. So what they did in this case is they found a treasure trove, if you will, of pots and jars that are about 2,500 years old. And they did a chemical analysis of what was in those jars to see what was used to make the mummies.

And they found extracts from juniper bushes, cypress trees, cedar trees, things that were grown really far away in the Mediterranean. And they even found resins that came from trees in Asia and Africa and some from India and Sri Lanka. So this was no backyard, by the seat of their pants–

IRA FLATOW: Yeah, it makes you wonder how they got that stuff there, you know?

ROXANNE KHAMSI: It does make you wonder how they got the stuff and why they got that stuff. What was it about this process that they really went the distance for these ingredients? And you have to wonder, why did they do it? Like all good science, it answers some questions, but then it opens up some new ones.

IRA FLATOW: Roxanne, it’s been a pleasure, as always. Thank you for joining us today.

ROXANNE KHAMSI: Thank you so much, Ira. It’s always a pleasure.

IRA FLATOW: Roxanne Khamsi, science writer based in Montreal, Quebec.

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