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Will Advanced Civilizations Build Habitable Planets or Dyson Spheres

Universe Today Feed - Fri, 11/01/2024 - 12:46pm

If there are alien civilizations in the Universe, some of them could be super advanced. So advanced that they can rip apart planets and create vast shells surrounding a star to capture all its energy. These Dyson spheres should be detectable by modern telescopes. Occasionally astronomers find an object that resembles such an alien megastructure, but so far, they’ve all turned out to be natural objects. As best we can tell, there are no Dyson spheres out there.

And when you think about it, building a Dyson sphere is the cosmic endgame of a capitalist dystopia. In the never-ending quest to capture and consume every last bit of energy, your civilization rips worlds asunder, moving heaven and earth to create an orbitally unstable, unlivable engine. If you can traverse light-years and transform planets, why not just move Earth-like planets and moons into a star’s habitable zone and have a nice cluster of comfy planets to live on? If this kind of stellar-punk civilization is out there, could astronomers detect it? This is the question behind a study on the arXiv.

The authors begin by noting that when Freeman Dyson proposed the idea in 1960, our solar system was the only known planetary system. Star systems were thought to be rare at the time, but now we know better. Most stars have planets, and even our solar system has a dozen water-rich moons that could be made habitable with a shift of their orbits and a bit of terraforming. Since this would be much easier than building a Dyson sphere, the authors argue that modified systems should be much more common. The only question is how to detect them.

One way would be to look for planetary systems that don’t seem to have formed naturally. For example, if you find a system with a dozen worlds in a star’s habitable zone and few other planets, that isn’t likely to have happened by chance. Less obvious would be to look for systems that are orbitally unusual. Perhaps the planets have orbital resonances that aren’t stable in the long term, or have unusually perfect orbits. Maybe the chemical composition of some worlds don’t match that of the system as a whole. Anything that stands out might be worth a closer look.

Using lasers to change a planet’s orbit. Credit: Narasimha, et al

Another way would be to look for signs of systems under construction. The authors note that planets could be moved or captured slowly over time using high-power directional lasers to accelerate them. Stray light from those lasers would be visible across light years. If we detect monochromatic laser light coming from a potentially habitable star, it could be aliens building a better home.

It’s not likely that we’ll find this kind of evidence, but the idea is no stranger than those of giant alien megastructures. Besides, it’s fun to think about just how many habitable planets you could pack into a single star system. It turns out to be quite a lot!

Reference: Narasimha, Raghav, Margarita Safonova, and C. Sivaram. “Making Habitable Worlds: Planets Versus Megastructures.” arXiv preprint arXiv:2309.06562 (2023).

The post Will Advanced Civilizations Build Habitable Planets or Dyson Spheres appeared first on Universe Today.

Categories: Science

Research uses lasers to detect landmines, underground objects

Matter and energy from Science Daily Feed - Fri, 11/01/2024 - 9:40am
Enough landmines are buried underground worldwide to circle Earth twice at the equator, but the identification and removal of these explosives is costly and time-consuming. New research could help solve the problem.
Categories: Science

Revolutionary high-speed 3D bioprinter hailed a game changer for drug discovery

Matter and energy from Science Daily Feed - Fri, 11/01/2024 - 9:38am
Biomedical engineers have invented a 3D printing system, or bioprinter, capable of fabricating structures that closely mimic the diverse tissues in the human body, from soft brain tissue to harder materials like cartilage and bone.
Categories: Science

Revealing causal links in complex systems

Computers and Math from Science Daily Feed - Fri, 11/01/2024 - 9:36am
SURD, an algorithm, reveals causal links in complex systems. Applications may include forecasting climate to projecting population growth to designing efficient aircraft.
Categories: Science

Fueling greener aviation with hydrogen

Matter and energy from Science Daily Feed - Fri, 11/01/2024 - 9:36am
Despite ongoing efforts to curb CO2 emissions with electric and hybrid vehicles, other forms of transportation remain significant contributors of greenhouse gases. To address this issue, old technologies are being revamped to make them greener, such as the reintroduction of sailing vessels in shipping and new uses for hydrogen in aviation. Now, researchers have used computer modeling to study the feasibility and challenges of hydrogen-powered aviation.
Categories: Science

Improving energy production by boosting singlet fission process

Matter and energy from Science Daily Feed - Fri, 11/01/2024 - 9:36am
Singlet fission (SF) is an exciton amplification phenomenon in which two triplet excitons are generated from a singlet exciton produced by the absorption of a single photon in chromophores. A team of researchers has demonstrated that SF can be promoted by introducing chirality and controlling chromophore orientation and arrangement. Their innovative study is expected to promote diverse applications in energy science, quantum, and information materials science, photocatalysis, solar cells, and life science.
Categories: Science

Using mathematics to better understand cause and effect

Computers and Math from Science Daily Feed - Fri, 11/01/2024 - 9:35am
A new method for determining causality gives scientists a more holistic view of the causal role that contributing factors play within just about any system.
Categories: Science

NASA's Hubble, Webb probe surprisingly smooth disk around Vega

Space and time from Science Daily Feed - Fri, 11/01/2024 - 9:35am
Teams of astronomers used the combined power of NASA's Hubble and James Webb space telescopes to revisit the legendary Vega disk.
Categories: Science

Research shows therapeutic virtual yoga program can be effective for chronic low back pain

Computers and Math from Science Daily Feed - Fri, 11/01/2024 - 9:35am
Researchers found that a 12-week therapeutic virtual yoga program for chronic low back pain can be a feasible, safe and effective treatment option.
Categories: Science

Microplastics increasing in freshwater, directly related to plastic production

Matter and energy from Science Daily Feed - Fri, 11/01/2024 - 9:35am
Microplastics have been steadily increasing in freshwater environments for decades and are directly tied to rising global plastic production since the 1950s, according to a new study by an interdisciplinary team. The findings provide insight into how microplastics move and spread in freshwater environments, which could be important for creating long-term solutions to reduce pollution, the researchers said.
Categories: Science

The Nation endorses Kamala Harris, but its interns object: “We cannot vote our way out of this genocide”

Why Evolution is True Feed - Fri, 11/01/2024 - 8:30am

Well, I’ll be. The group of interns at the left-wing The Nation have objected to the magazine’s recent endorsement of Kamala Harris and published their gripes. Now why would that happen? We all know that many editors and reporters at the Washington Post objected to the paper’s failure to endorse Kamala Harris, but this kind of reversal is unexpected.  Well, sort of—unless you know how “progressive” young Leftists are beginning to change journalism.

So why the beefing? It’s Israel, Jake!

Here, from the “activism” section of the magazine (!), is the long gripe by The Nation‘s interns (click to read for free):

An excerpt giving the tenor of their rage:

We, The Nation’s current interns, find this endorsement unearned and disappointing. We have a different interpretation of the magazine’s abolitionist legacy, one that says a publication committed to justice must refrain from endorsing a person signing off on genocide. We do not support Donald Trump, but to champion Harris at this moment is to ignore the atrocities that are being carried out with weapons supplied by the Biden-Harris administration.

The Nation’s endorsement notes that on foreign policy the “positive case [for Harris] is harder to make,” adding that “she has failed so far to offer anything more substantive to the millions of Americans…desperate for an end to America’s unconditional support for Israel’s brutal war on Gaza.” Yet it goes on to endorse her anyway—implying that domestic concerns are somehow more important. We disagree. On the grounds of Gaza alone, Harris should not have received The Nation’s endorsement.

In the 12 weeks since she effectively became the Democratic nominee, Harris has failed to differentiate her policies from Joe Biden’s blank-check support for genocide. Instead, she repeats the same bland pronouncements about the need for a ceasefire and uses the same passive-voice support for the idea of Palestinian “freedom and self-determination.” Again and again, she has been asked by Palestinian, Arab, and Muslim voters, along with a broad coalition of Democrats of conscience, to offer an alternative, and again and again she has refused. She would not even allow a pre-vetted Palestinian supporter of hers to speak at theDemocratic National Convention.

We have watched this abdication of moral responsibility by the Democratic nominee with a growing sense of dismay. As young journalists, we think of our colleagues in Gaza. Israel has killed more than 175 journalists in Gaza since last October—and right now, with US support and the Western media’s indifference, Israel is effectively issuing hit lists of reporters in Gaza. During the last year, The Nation has published dispatches from Palestinian journalists, from 14-year-old Lujayn to the journalist Mohammed Mhawish, both of whom have survived air strikes, most likely from US-made weapons. We cannot advocate for a person who is complicit in the murders of fellow journalists and the bombing of colleagues whose pieces we have fact-checked.

Even when they try to leaven  Harris’s position as a perpetrator of genocide with her “good” domestic policies, they can’t resist bringing up Gaza again and again:

Harris, for instance, promises to provide tax credits to families with newborns and to sign a law to restore the right to abortion nationwide. Yet her commitment to the welfare of children doesn’t extend to the more than 17,000 kids killed in Gaza, hundreds of whom died from inadequate postnatal care like incubators. She will fight for reproductive care in the United States, but in Gaza, tens of thousands of mothers have or will give birth without access to doctors, pain relief, hospitals, or food and water.

Harris also pledges to strengthen our healthcare system. But in Gaza, as many as 1,000 healthcare workers have been killed, 30 of 36 hospitals have been damaged or destroyed, and fewer than half are even partially functional. People routinely die from the blockade of basic sanitary equipment, ordinary medicines, and vaccines.

Harris’s plans to relieve the housing crisis in the United States ring hollow next to her support for Israel’s destruction of homes in Gaza, the West Bank, and Lebanon. With the Biden-Harris administration’s full knowledge and aid, 90 percent of Gazans have been forcibly displaced, and hundreds of thousands of homes have been damaged and destroyed. Nor has the administration done anything to stop the demolitions of houses and illegal expansion of settlements in the West Bank.

So who do the interns think the magazine should endorse for President? Nobody, of course. It’s curious that the Washinton Post would get slammed for not endorsing anybody, but the interns haven’t been slammed (or so I’ve seen) for the same action. Of course accusing Israel of genocide is perfectly okay with the “progressive” Left. One more bit from this execrable whine:

There will be people wondering whom we would endorse, if not Harris. Our answer is that we choose not to endorse any party’s candidate for president. We know that a second Trump presidency would be a disaster, but we believe that we cannot vote our way out of this genocide. And while some of us will be voting for president in November—and some of us will not—we all reject the idea that democracy will be safe under a Harris administration.

This is, to my mind, ridiculous, and exemplifies the Jew-hatred that is permeating young people and gradually working its way up into journalism, government, and corporations.  You don’t have to be a rocket scientist to realize that, in fact, the genocide is on the side of Hamas, which put into words (and acts repeatedly on) its desire to eliminate Israel. It is Hamas that deliberately tries to kill Jewish civilians, while Israel does its best to avoid killing civilians (its ratio of civilians killed to terrorist fighters killed is one of the lowest of modern times). Does Hamas warn Israeli civilians to get out of the way when it fires a rocket? No, it wants to kill civilians. It targets civilians, both with rockets and, of course, personally, as the October 7 massacre and subsequent acts of terrorism attest.

And, of course, we all know that part of Hamas’s strategy is to ensure that Gazan civilians get killed as a way of winning the world’s sympathy. They do this by embedding their fighters and rocket launchers among civilians and even in hospitals and humanitarian zones.  That guarantees not only that civilians will die as “collateral damage” (I hate that phrase, since all non-combatant human life should be preserved), but also that journalists, who have to be close to the action, will die as well. As the saying goes—and you know it’s true—”If Hamas put down its weapons, the war would be over. If Israel put down its weapons, all the Jews would be killed and Israel would disappear.” The reason Israel sustains fewer casualties is that it has more weapons than do the Palestinians as well as defense systems against rockets fired by Islamist terrorists.

I regard it as a touchstone of ignorance (willful ignorance, not simply “failure to know”) when someone accuses Israel of genocide when it’s palpably clear that Israel is not engaged in a program of eliminating all Palestinians, whose population has grown rapidly in the last decade. And of course where are the accusations of genocide against Hamas? I haven’t heard any lately, except, perhaps, by Israelis, but even then I can’t think of any.

I can’t print here what I think of these ignorant interns since this is a family-friendly site. Just let me say that I hope to Ceiling Cat that they don’t take over journalism and politics. Harris is already weakening American support of Israel by repeatedly calling for a cease-fire, which if effected now, would simply allow Hamas to regroup and continue perpetrating terrorism. If I were a paper and had to endorse a candidate (of course I don’t think papers should be endorsing candidates), it would of course be Harris. But to withhold that approbation because of a supposed “genocide” is sheer stupidity.

The abiding sin of the interns is their failure to blame Hamas rather than Israel for the deaths of Gazan civilians.  If beginning in 2005, a subset of Palestinians was not intent on killing Jews and getting rid of Israel, Gaza would now be a Mediterranean paradise, rich and full of big-spending tourists and beach resorts.

Categories: Science

There may be a cosmic speed limit on how fast anything can grow

New Scientist Feed - Fri, 11/01/2024 - 7:28am
Alan Turing's theories about computation seem to have a startling consequence, placing hard limits on how fast or slow any physical process in the universe can grow
Categories: Science

World's largest tree is also among the oldest living organisms

New Scientist Feed - Fri, 11/01/2024 - 7:14am
DNA analysis suggests Pando, a quaking aspen in Utah with thousands of stems connected by their roots, is between 16,000 and 81,000 years old
Categories: Science

I have landed (and tout a book).

Why Evolution is True Feed - Fri, 11/01/2024 - 6:32am

All day yesterday I was making my way back to Chicago from Ivins, Utah: first, a two-hour drive to Las Vegas, then a two-hour wait in the airport, with the flashing and music of slot machines IN THE WAITING AREA, and finally a four-hour flight back home. I am exhausted. Which is to say: posting will be very light today—if there is any.

But on the way home I read Salman Rushdie’s latest book, Knife: Meditations After An Attempted Murder, which came out in April. Click the screenshot below to go to the Amazon site. I have to say that the cover is wonderfully designed given the contents:

It’s a short (200-page) account of the attempted murder of Rushdie on August 12, 2022 by accused perp Hadi Matar, a Lebanese-American likely trying to fulfill the fatwa issued on Rushdie in 1989 by the Ayatollah Khomeini.  The Ayatollah considered Rushdie’s book The Satanic Verses as anti-Muslim blasphemy, and called for the author’s assassination. A $3 million bounty accompanied the fatwa. Rushdie went into hiding, but several people connected with the book were killed.

Finally, after 33 years, the fatwa was fulfilled when Matar ran at Rushdie as the author was about to address a Chautauqua, New York audience about the need for a “safe space” for politically demonized writers.  Matar apparently stabbed Rushdie 15 times in the neck, eye, chest, and hand, blinding him in one eye and rendering his left hand largely useless. For several days Rushdie hovered between life and death, but thanks to expert trauma care, he survived. His eye remains but its sightless, and his hand is only minimally useful. But, Rushdie avers, he was largely saved by the love of his (fifth) wife, the African-American poet Rachel Eliza Griffiths. In many ways the book is a paean to Griffiths, who was by his side the whole way, and the description of their mutual love is quite moving.

Rushdie, as you see from this book, is back in action, and on to another novel. I have read only one of his, but it was a corker: Midnight’s Children, which I picked up for a pittance in a used-book stall in New Delhi. I was mesmerized by the novel, which won not only a Booker Prize, but the “Booker of the Bookers“, an award for the 25th anniversary of the Prize. In other words, it was judged the best of the 25 Booker winners.  I’ve read a fair number of Booker-Prize winners, and think Rushdie’s award was well deserved. Midnight’s Children is a great classic, a magical-realism account centered on the partition of India in 1947. PLEASE read it if you haven’t.

Sad to say, that is the only novel of Rushdie’s I’ve read, and I must catch up. He’s written about 20 of them, apparently of varying quality, including an earlier autobiography called Joseph Anton, dealing with his post-fatwa journey. But I hear some of the novels are gems, and I must get to them.  He’s a likely future winner of the Nobel Prize for Literature, which I think has been delayed only because Stockholm fears Muslim backlash if Rushdie wins.

As for Knife, it’s a gripping short read and the details of Rushdie’s assault and subsequent recovery make the book one that’s hard to put down. I recommend it highly for a short read and for those interested in Rushdie.  A fair amount of the last part of the book is a fictionalized dialogue between Rushdie and his assailant, which changes the pace of the book substantially. At first I didn’t like this bit, but the more I read it, the more I enjoyed it. It is, I suppose, a way for Rushdie to come to terms with Matar and his attack, trying to suss out why a New Jersey resident would knife the writer after so many years.

Below is a Wikipedia photo of the post-attack Rushdie. He decided not to have his eye removed but rather to hide it with a dark lens in his glasses. He does have macular degeneration in his other eye, and fears above all that he will go blind. But it looks as though they’ve stabilized his condition:

Elena Ternovaja, CC BY-SA 3.0, via Wikimedia Commons

Matar, by the way, is still awaiting trial. They delayed it because his public defender argued that Rushdie’s published account was essential for Matar’s defense.

Categories: Science

One in 20 new Wikipedia pages seem to be written with the help of AI

New Scientist Feed - Fri, 11/01/2024 - 5:55am
Just under 5 per cent of the Wikipedia pages in English that have been published since ChatGPT's release seem to include AI-written content
Categories: Science

Friday: Hili dialogue

Why Evolution is True Feed - Fri, 11/01/2024 - 5:04am

Meanwhile, in Dobrzyn, Hili has a message for us all:

A: What are you thinking about?
Hili: About hope in hopelessness.
A: And what is your conclusion?
Hili: That it requires intelligence, knowledge and craftiness.

Ja: O czym myślisz?
Hili: O nadziei w beznadziejności.
Ja: I jaki wniosek?
Hili: Wymaga inteligencji, wiedzy i przebiegłości.

Categories: Science

Cloud-inspired material can bend light around corners

New Scientist Feed - Fri, 11/01/2024 - 3:00am
Light can be directed and steered around bends using a method similar to the way clouds scatter photons, which could lead to advances in medical imaging, cooling systems and even nuclear reactors
Categories: Science

The best new science fiction books of November 2024

New Scientist Feed - Fri, 11/01/2024 - 2:00am
From Harlan Ellison to Haruki Murakami, via an intergalactic cooking competition, this month has plenty of science fictional treats on offer
Categories: Science

When Dolphins Network

Skeptic.com feed - Fri, 11/01/2024 - 12:00am

David Lusseau always wanted to be a biologist. “Well, either biologist or clown,” he adds, “but I realized there was not much money in clowning.” When Marie the dolphin entered Lusseau’s life, she sealed the deal for him becoming a biologist. A bottlenose dolphin (Tursiops truncatus) who swam in the waters near the village of Cerbère on the border between France and Spain in the late 1980s, Marie set seventeen-year-old Lusseau on a path that would one day lead him to study social networks in her species. “When you look in the eyes of a dolphin, you realize there is a lot going on,” Lusseau says, reminiscing on his time with his cetacean friend. “It is something that is very hard to express or grasp or explain in a factual matter, but spending time with [Marie] got me interested in … trying to understand how dolphins work, [in what] I perceived as another intelligent species on the planet.”

As an undergraduate, Lusseau spent time as a research assistant working with a group studying bottlenose dolphins in Florida. When out in the water, he encountered dolphins swimming on their own or in pairs. On occasion he bumped into a trio, but dolphins always seemed to be doing their own thing, just in the company of one or two others. That view of dolphin sociality, or the lack of it, changed dramatically when Lusseau began his PhD research in the late 1990s at the University of Otago in New Zealand. His dissertation focused on conservation biology in bottlenose dolphins in a fjord called Doubtful Sound, but the social behavior of the dolphins there hit him like a ton of bricks. As soon as he got there, he encountered not lone dolphins, duos, or trios, but groups of thirty or more dolphins schooling and moving about in a coordinated manner. These were very different animals from the solo dolphins and very small dolphin groups he had studied in Florida.

Each day Lusseau rose at 4 a.m., grabbed some breakfast, swatted away an endless barrage of midges, and arrived at Doubtful Sound before the sun rose. He’d board a 14-foot boat, locate a group of dolphins, and do focal animal sampling, cycling through dolphins, each recognizable by natural markings on their dorsal fins, often from shark attacks. Doubtful Sound can be stunningly beautiful, but it is at a latitude called the “roaring forties” because of the strong winds from the west and six- to eight-foot waves at times, which make for rough going when watching dolphins from a boat.

As he spent time with the dolphins, Lusseau began thinking about how to understand their complex social dynamics, but he couldn’t quite figure out the best way to proceed. On one of his stints back at the University of Otago, Lusseau recalls reading a Proceedings of the National Academy of Sciences paper on social networks written by physicist Mark Newman and others. Soon after that, he emailed Newman, telling him, “I think you are doing really cool stuff and I can understand it, because you write so well. Would you like to have a look at what we’re doing?” Newman was interested. It wasn’t long before he and Lusseau were coauthoring papers on dolphin social networks. But before they penned any coauthored papers, Lusseau published a 2003 paper in the Proceedings of the Royal Society of London that is widely regarded as the first study explicitly on social networks in nonhumans.

Unlike animal social network papers in today’s journals, where readers are acquainted with how networks operate, to put readers in the right frame of mind in 2003, Lusseau opened his Royal Society paper using a strategy that Darwin had employed in On the Origin of Species. The idea was to introduce a phenomenon that readers already knew about (in Darwin’s case artificial selection, as in selection of different breeds of pigeons) and then make the case that what followed (natural selection), though it appeared radical, was really just another variety of what he had just discussed. In Lusseau’s paper, the opening sentences read: “Complex networks that contain many members such as human societies … the World Wide Web (WWW) … or electric power grids … permit all components (or vertices) in the network to be linked by a short chain of intermediate vertices.” And before readers knew it, they were learning about such social networks in dolphins.

Lusseau constructed dolphin networks based on thousands of observations, and one metric he looked at was network diameter, which measures the average shortest path between nodes. To introduce network diameter to readers, Lusseau first discussed psychologist Stanley Milgram’s “small world” research from the late 1960s. “The global human population seems to have a diameter of six,” wrote Milgram, “meaning that any two humans can be linked using five intermediate acquaintances.” The party version of Milgram’s small world is the parlor game “six degrees of Kevin Bacon.” The rules are simple: players choose a movie actor and then connect that actor to another that they played alongside in a film, repeating the process over and over, trying to link their original actor to movie star Kevin Bacon—who once quipped “he had worked with everybody in Hollywood or someone who’s worked with them”—in no more than six connections. It turns out the dolphin small world in Doubtful Sound is smaller than the human one (including Kevin Bacon’s), both in the size of the network and network diameter, the latter of which is approximately three, meaning any two dolphins in Doubtful Sound can be linked using two intermediate acquaintances.

Lusseau wondered what would happen if the dolphin network was culled by, for example, shark predation. To do this, using the network data he had collected, he built a computer algorithm that simulated predation, reducing the network size 20 percent by randomly removing 20 percent of the dolphins. The small world of the dolphins, it turned out, was unaffected by such a reduction. But if instead of randomly selecting individuals to remove from the network, Lusseau simulated removal of the 20 percent of dolphins who had the greatest number of ties to others, network diameter increased, which had the effect of slowing information transfer within the network.

As he came to know his dolphins better, Lusseau discovered that some individuals in Doubtful Sound give signals that affect group movement associated with finding new resources, including food. Side flopping, in which a dolphin leaps from the water and lands on its side, is seen only in males when they initiate a move to a new location, while upside-downing, in which an individual rolls onto its ventral side and slaps the water to signal an end to a group move, is seen almost exclusively in females. But only a few males do all the side flopping, and only a few females do all the upside-downing. Lusseau wanted to know if a network analysis would shed light on exactly which males and which females. It did. Males initiating and females terminating travel had higher betweenness— they were key hubs in this traveling/foraging network—than their non-signaling counterparts.

In a few populations of bottleneck dolphins on the other side of the planet, in Brazil, signaling and networking is not sometimes about feeding opportunities—they are always about that. And the dolphins have, rather remarkably, added humans to their feeding networks.

For more than three decades, ethologist Paulo Simões-Lopes has been studying dolphin populations in the lagoon systems along the coastline near Laguna, Brazil, about 800 kilometers south of São Paulo. The dolphins in nine populations along that stretch do something that no other dolphins—and almost no other animals, period— do. They not only network with each other, but cooperate with humans to secure more food for both themselves and their primate partner.

Each autumn, a huge mullet migration takes place in southern Brazil. Both the dolphins and the fishermen see the fish as prize prey. Up to fifty fishers, wading waist deep in very cold water, wait for the chance to cast large circular nylon nets called tarrafa over schools of mullet. The problem for the fishers is that the water is murky, and it is next to impossible to see the fish. The problem for the sixty or so dolphins at Laguna is that compared to their other prey, mullet are large and hard to catch. But dolphins aren’t especially troubled by murky water, as they detect mullet using echolocation, a built-in sonar system that would be the envy of most engineers.

Dolphins produce sound waves in their nasal sacs and focus those waves through fatty tissue and fluid in their foreheads. Once the sound waves are shot out into the water, they travel until they bump into an object, at which point they bounce back to the dolphins, who use their lower jaw as a receiver. From the lower jaw, the waves travel to the inner ear and then to the brain. Objects of different sizes and densities reflect back sound waves of different frequencies, and the dolphins use that information to “see” what is in the water around them. When their sonar detects mullet, dolphins signal fishers that the fish are present by curving their backs and then slapping their heads or their tails on the water surface. The fishers then cast their tarrafa and pull in loads of mullet. The confused mullet who escape the tarrafa often swim right into the mouths of waiting dolphins. It’s the perfect win-win situation.

Laguna newspapers from the late 1890s featured articles about this dolphin-human mutualism, and so Simões-Lopes knows that, at the very least, it has been going on for more than 130 years. And though many dolphins don’t signal fishers, every fisher knows which dolphins do. “It is famous [in southern Brazil],” Simões-Lopes says. “I grew up watching those dolphins … I would sit on a rock in the canal and watch for hours. I knew it was unusual … I knew there were dolphins in a big harbor farther south where dolphins and fishermen don’t interact.”

Today Simões-Lopes has a team of ten working with him, but he began on his own in 1988. Soon thereafter, he entered a PhD program and built his dissertation around his research on the dolphin-human foraging mutualism. Each day he brought a folding chair with him and set it up on a rock, watching the dolphins through his binoculars, taking photos—he had compiled a mug book with photos of all the dolphins in the lagoon—and filling notebook after notebook with data on dolphins signaling fishers.

Simões-Lopes began to know the fishers, and they began to know him. He also was starting to get a good feel for which dolphins at Laguna signaled the fishers and which did not. Not surprisingly, the fishers also kept tabs, telling Simões-Lopes about the “good dolphins” (who signaled fishers) and the “bad dolphins” (who did not). The fishers know not only which dolphins signal, but which dolphin will give which signal: “Each dolphin gives the signal in a different way,” one fisher said, “and we need to know [the different signals] in order to catch the fish.” Another fisher was more of a romantic, telling Simões-Lopes and his colleagues, “This is beautiful. It doesn’t happen everywhere.”

The more that Simões-Lopes thought about those “good” dolphins and “bad” dolphins, the more he wanted to understand them better. Years later Mauricio Cantor joined Simões-Lopes’s team; Cantor had worked with Hal Whitehead, a leader in early social network analysis. Simões-Lopes and Cantor decided that a network analysis might help them delve deeper into the between-species cooperation they observed on a daily basis. In 2008, they contacted David Lusseau, who had done the network studies on bottlenose dolphins in New Zealand, and asked if he would be interested in serving as a sort of conceptual consultant specializing in social networks. Lusseau was more than happy to join their team.

This article appeared in Skeptic magazine 29.3
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Simões-Lopes and his team assumed dolphins learn how to signal humans from other signalers they associate with, so for their social network analysis, they were especially interested in whether signaling dolphins preferred spending time with other signaling dolphins, both when they were chasing mullet into nets and, just as importantly, when they were not. To test whether there were cliques of signalers and cliques of dolphins who didn’t signal, Simões-Lopes’s team looked at clustering coefficients of sixteen cooperators and nineteen dolphins who did not signal and cooperate with fishers.

What they discovered were three cliques within the larger network of the thirty-five dolphins. Clique 1 had fifteen dolphins: each and every one of them cooperated with the local fishers. Dolphins in this clique associated with one another not just during the autumn mullet fishing season but the rest of the year as well. Clique 2 had a dozen dolphins, none of whom cooperated with fishers, and dolphins in this clique were not as well connected to one another as the individuals were in Clique 1. Clique 3 was made up of eight dolphins: seven never cooperated with fishers, but one—dolphin 20—did. And of all thirty-five dolphins in the network, it was dolphin 20 who spent the most time interacting across cliques, acting as what Simões-Lopes and his colleagues call a “social broker” between the signalers and non-signalers.

This behavior is all wonderfully complex, and we humans—and I don’t just mean the artisanal fishers of Laguna—should be grateful to play a role in understanding it.

Excerpted and adapted by the author from The Well-Connected Animal: Social Networks and the Wondrous Complexity of Animal Societies by Lee Alan Dugatkin, published by The University of Chicago Press. © 2024 by Lee Alan Dugatkin. All rights reserved.

About the Author

Lee Alan Dugatkin is an evolutionary biologist and a historian of science in the Department of Biology at the University of Louisville. He is the author of sixteen books and more than 200 articles in such journals as Nature, The Proceedings of the National Academy of Sciences, and The Proceedings of the Royal Society of London. Dr. Dugatkin is contributing author to Scientific American, The American Scientist, The New Scientist, and The Washington Post. His latest book is The Well-Connected Animal: Social Networks and the Wondrous Complexity of Animal Societies.

Categories: Critical Thinking, Skeptic

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