Readers amazed by Amasia

Saved by the Bell
Physicists used light from stars to perform a cosmic Bell test, which verified that quantum particles were indeed “spooky,” Emily Conover reported in “Quantum effect passes space test” (SN: 1/21/17, p. 12).

Reader George Mitchell took issue with Conover’s description of entangled photons before they are measured as having multiple polarizations at once. “We don’t know the direction of their polarization,” Mitchell wrote. “It is undefined.”

“Multiple polarizations” in this context is meant to indicate that there are multiple possible outcomes of a polarization measurement; the particle does not have a definite polarization that is simply unknown. “Bell tests like the one in the a­rticle confirm this interpretation,” Conover says (SN Online: 1/27/16).
It’s similar to how Schrödinger’s cat can be in a “superposition” of both alive and dead at the same time (SN: 11/20/10, p. 15). “It’s not that we don’t know whether the cat is alive or dead; it’s both,” she says. “This is hard to wrap one’s head around.” In any case, it is effectively impossible to put a real cat in a superposition, because it is too large to display the strange properties of quantum mechanics. “But for particles,” she says, “this is acceptable behavior.”

Land ho
From Nuna to Pangaea, shifting landmasses have repeatedly reshaped Earth’s surface. Researchers are now picturing a future s­upercontinent dubbed Amasia, due in 250 million years, Alexandra Witze reported in “Supercontinent superpuzzle” (SN: 1/21/17, p. 18).

Reader Pierre Grillet wondered how subduction — the process by which a tectonic plate is pushed beneath another tectonic plate — could pull continents apart. “I would suggest that a different mechanism is also at work here. Rising material must balance crust material being subducted into the mantle,” he wrote. “It would make sense that this rise should occur in the center of the plate, where the mantle is hotter. Rising material would then spread sideways, pushing the sides of the plate over the oceanic crust and pulling the plate apart.”

The process Grillet describes is a theory proposed by some researchers. Other researchers have doubts (SN: 4/4/15, p. 13). “Plumes of hot material rising from the mantle could rip continents apart, but the plumes would have to rise up at weak points along continental boundaries, which seems unlikely,” says Thomas Sumner, Science News’ earth sciences writer. A competing theory covered in the story suggests that subduction tears continental plates apart by pulling at their edges.
Power up
A variety of next-generation batteries promise to store energy more efficiently, providing power for longer periods, Susan Gaidos reported in “Charging the future” (SN: 1/21/17, p. 22).

Reader Tom Wicker was disappointed that the beginning of the story equated power and energy. “Everybody wants more power from their batteries,” Gaidos wrote, citing smartphone, laptop and electric-car batteries as examples.

“Laptop batteries can supply more than enough power. You need to charge them frequently because of the limited amount of energy they store,” Wicker wrote. “It is of course correct that drawing more power, more energy per unit time, from a battery will drain it faster. But that is true even though the battery may have no problem supplying the required amount of power. It just can’t do that for as long as required due to insufficient energy storage.”

Wicker’s distinction between energy and power is correct, Gaidos says. “When talking about batteries, the term ‘portable power’ is frequently used, when what is really meant is portable energy. The research under way, as described in the story, aims to create batteries with high power that can maintain that power through a large number of recharge cycles,” she says.

Rare triplet of high-energy neutrinos detected from an unknown source

Three high-energy neutrinos have been spotted traveling in tandem.

The IceCube Neutrino Observatory in Antarctica detected the trio of lilliputian particles on February 17, 2016. This is the first time the experiment has seen a triplet of neutrinos that all seemed to come from the same place in the sky and within 100 seconds of one another. Researchers report the find February 20 on arXiv.org.

Physicists still don’t know where high-energy neutrinos are born. The three neutrinos’ proximity in time and space suggests the particles came from the same source, such as a flaring galaxy or an exploding star. But the scientists couldn’t rule out the possibility of a fluke — the triplet could simply have been the result of accidental alignment between unassociated neutrinos.

Eight different telescopes followed up on the neutrino triplet, checking for some sign of the particles’ origins. The telescopes, which searched for gamma rays, X-rays and other wavelengths of light, found nothing clearly associated with the particles. But scientists were able to rule out some possible explanations, like a nearby stellar explosion caused by the collapse of a dying star.

Online reviews can make over-the-counter drugs look way too effective

Here’s one good reason why people often take medications and use health products that don’t live up to expectations or just don’t work — digital word of mouth.

The reviews can be glowing. Take this scuttlebutt about a cholesterol treatment: “I have been using this product for 2 years. Within the first 3 – 4 months my cholesterol was down 30 points. Just got cholesterol tested last week: down from 245 to 196.”

That’s incredible. It might even be true. But the big picture is alarming: Patients’ online reviews of three over-the-counter drugs — two for lowering cholesterol and one for losing weight — greatly exaggerate how well these substances actually work for most people, says psychologist Mícheál de Barra of the University of Aberdeen in Scotland. Online reviewers portray these medications as working three to six times better than they do in clinical trials that randomly assign drugs or placebos to broad samples of volunteers, he says.

“To learn what works in medicine, you need systematically collected data, usually randomized clinical trials,” de Barra says. “It’s very risky to rely on observations and word of mouth, whether it’s electronic or in person.”

Online reviewers probably aren’t lying, at least not in most cases. Neither are online review readers unrealistically optimistic about health treatments. The problem is that people who benefit most from a medication are especially apt to post their experiences online. Review readers get bamboozled by a wave of positive recommendations that don’t accurately represent how a drug works, or doesn’t work, for people in general.

The duping doesn’t end there. Direct word of mouth about medical treatments, as well as glowing testimonials about health products in advertisements, also traffic in positively skewed information.

In some cases, science does, too. Researchers have recently raised alarms about the “file-drawer problem,” in which studies that find no statistical effects are not published (SN: 5/19/12, p. 26). Published studies reporting positive effects then look unjustifiably bulletproof.

Clinical trials can tilt results in other ways as well. Authors of published trials often fail to preregister details of what they plan to study and how they’ll measure it, enabling data manipulation, selective reporting of results and self-serving interpretations of findings. Clinical trials report patients’ “average” responses to, say, an anticholesterol drug, but do a poor job of predicting which individuals will benefit from that treatment. “Published evidence from randomized trials is already an amalgam of evidence-based medicine and hearsay,” notes Stanford University epidemiologist John Ioannidis.
Online reviews are just old-fashioned word of mouth with a global bullhorn. But they offer one way to quantify the positive bias inherent in so much communication about medical treatments. Patients’ medication reviews that include numerical information, such as cholesterol levels before and after taking an anticholesterol drug, represent what Ioannidis calls “evidence-based hearsay.” Even if patients’ reviews rate treatments with a star system rather than including quantified measures of some kind, those opinions become powerful hearsay evidence for other patients, Ioannidis suspects.

De Barra evaluated 908 online reviews of two cholesterol reduction products, Benecol caramel smart chews and CholestOff, written on or before March 18, 2015. He also assessed 767 reviews of a weight-loss drug, Alli (orlistat), written on or before February 28, 2015.

Benecol reviewers reported a not-too-shabby average cholesterol decline of 45 milligrams per deciliter, versus a small average decline of 14 milligrams per deciliter in nine clinical trials. Respective numbers for CholestOff were 31 milligrams per deciliter and 13 milligrams per deciliter. Alli reviewers reported an average weight loss of about 10 kilograms after taking the drug for three months, versus an average of about two or three kilograms in two clinical trials. That disparity widened slightly after taking Alli for seven months.

Each drug garnered mainly positive reviews, some reporting effects far larger than the average, peppered with a few pans, De Barra reports in the March Social Science & Medicine.

What’s particularly concerning is that these three medications displayed small or negligible effects in clinical trials that probably already inflated how well the drugs work, Ioannidis says. So people searching for help in lowering cholesterol or shedding pounds may instead be getting a massive dose of disappointment from online reviews.

Online reviews can also exaggerate a treatment’s worst effects, whether real or alleged. Evidence-based hearsay may be particularly catchy online and in person when it’s frightening, de Barra suspects.

The anti-vaccination movement provides a potent example, due in part to the success of vaccines. When people face no immediate threat from measles or other infectious diseases, anti-vaccine stories may go viral, so to speak, thanks to misapplied but deeply felt intuitions. Two cognitive scientists, Helena Miton of Central European University in Budapest and Hugo Mercier of the Cognitive Sciences Institute in Bron, France, proposed this scenario in the November 2015 Trends in Cognitive Sciences.

However medical treatments acquire halos or horns, only well-conducted, transparent clinical trials can identify effective medical treatments, such as childhood vaccinations, and their potential side effects, Ioannidis says. But an ominous research trend is gathering steam, he warns. Researchers, professional societies, funders and lobbyists increasingly push to replace clinical trials of randomly selected volunteers with studies of interventions for select samples of people who eat certain foods, take certain drugs or behave in certain ways. The latter investigations may inflate a treatment’s effects even more than online patient reviews do, Ioannidis asserts.

Perhaps a new wave of studies showing how evidence-based hearsay misrepresents many medications will be just what the doctor ordered to resuscitate evidence-based medicine, he muses.

Palace remains in Mexico point to ancient rise of centralized power

Remnants of a royal palace in southern Mexico, dating to between around 2,300 and 2,100 years ago, come from what must have been one of the Americas’ earliest large, centralized governments, researchers say.

Excavations completed in 2014 at El Palenque uncovered a palace with separate areas where a ruler conducted affairs of state and lived with his family, say archaeologists Elsa Redmond and Charles Spencer, both of the American Museum of Natural History in New York City. Only a ruler of a bureaucratic state could have directed construction of this all-purpose seat of power, the investigators conclude the week of March 27 in Proceedings of the National Academy of Sciences.

The royal palace, the oldest such structure in the Valley of Oaxaca, covered as many as 2,790 square meters, roughly half the floor area of the White House. A central staircase connected to an inner courtyard that probably served as a place for the ruler and his advisors to reach decisions, hold feasts and — based on human skull fragments found there — perform ritual sacrifices, the scientists suggest. A system of paved surfaces, drains and other features for collecting rainwater runs throughout the palace, a sign that the entire royal structure was built according to a design, the researchers say.

El Palenque’s palace contains no tombs. Its ancient ruler was probably buried off-site, at a ritually significant location, Redmond and Spencer say.

New worm-snail is a super slimer

A new species of worm-snail is rather snotty. Thylacodes vandyensis shoots out strands of mucus that tangle together, building a spiderweb-like trap for plankton and other floating snacks, researchers report April 5 in PeerJ.

Other worm-snails use this hunting technique, but T. vandyensis stands out because of the “copious amounts of mucus” it ejects, says coauthor Rüdiger Bieler. This goo net, which can stretch up to 5 centimeters across, exits the animal’s tentacles at, of course, “a snail’s pace,” jokes Bieler, a curator at the Field Museum of Natural History in Chicago.

Like other worm-snails, T. vandyensis permanently glue themselves to spots. Bieler found T. vandyensis, which typically grow half as tall as a pinkie finger, on the hull of a sunken ship in the Florida Keys. But they don’t belong there: DNA analysis shows that this invasive species’ closest relatives are in the Pacific Ocean. The worm-snail may have made its way to the Atlantic as a stowaway on a ship.

HPV vaccine as cancer prevention is a message that needs to catch on

Cancer prevention isn’t the first thing that comes to many parents’ minds when they consider vaccinating their preteens against human papillomavirus, or HPV. And the fact that HPV is transmitted sexually gives the vaccine more baggage than a crowded international flight. But what gets lost in the din is the goal of vaccination, to protect adolescents from infection with HPV types that are responsible for numerous cancers.

Newly released estimates show just how prevalent HPV infections are in the United States. In April, the U.S. Centers for Disease Control and Prevention reported for 2013-2014 that among adults ages 18 to 59, 25 percent of men and 20 percent of women had genital infections with HPV types that put them at risk of developing cancer.

That’s just a snapshot in time. For those who are sexually active, more than 90 percent of men and 80 percent of women can expect to become infected with at least one type of HPV during their lives. About half of those infections will be with a high-risk HPV type.

“People who think, ‘I’m not at risk,’ are really not understanding the magnitude of this virus,” says cancer epidemiologist Electra Paskett of Ohio State University in Columbus.

HPV is the most common sexually transmitted infection in the United States. The HPV group of viruses includes low-risk and high-risk types. Low-risk types 6 and 11 are responsible for 90 percent of all genital warts. The high-risk types of HPV can cause cancer, and the two behind most HPV-related cancers are types 16 and 18. Seventy percent of cervical cancers can be traced back to types 16 and 18, while type 16 also causes cancers of the anus, vagina, penis and the oropharynx, the part of the throat at the back of the mouth. HPV spreads by sexual contact, either vaginal, anal or oral.
Nationally, from 2011 to 2014, 11 percent of men ages 18 to 69 had an oral infection with any type of HPV, and for nearly 7 percent of men, it was a high-risk type, the CDC’s National Center for Health Statistics estimated in its April report. For women in this age group, it was 3 percent and 1 percent, respectively.

The numbers are far worse when it comes to genital HPV infections. During 2013 to 2014, 45 percent of men and 40 percent of women ages 18 to 59 had genital infections with any type of HPV. One in four men and one in five women in this age group were infected with a high-risk type.

“It’s a wake-up call for both genders, but particularly for males,” says Jessica Keim-Malpass, a nurse scientist at the University of Virginia in Charlottesville.

For an estimated 19,200 women and 11,600 men each year, HPV infections result in a cancer diagnosis.

Vaccination could greatly relieve this cancer burden. Three different HPV vaccines have been available in the United States. The first, introduced in 2006, covered low-risk types 6 and 11 and high-risk types 16 and 18. The most recent HPV vaccine protects against these four types as well as five more high-risk types, and is the only vaccine currently distributed nationally. A federal advisory committee recommended routine vaccination against HPV at 11 or 12 years of age in 2006 for girls and in 2011 for boys.

But the HPV-cancer prevention message doesn’t seem to be getting through in the United States. HPV vaccination rates lag behind the national coverage goal of 80 percent for 13- to 15-year-olds. In 2015, among U.S. adolescents ages 13 to 17, six out of 10 girls and five out of 10 boys had gotten at least one shot in a three-shot series. But only four out of 10 girls and three out of 10 boys had completed the series.

What’s with the lackluster response?

Parents are part of the issue. “They don’t know about the vaccine, or they have fears about safety, or they say ‘My child is not going to be at risk for HPV infections,’” Paskett says.

The safety of all three vaccines was established in large clinical trials before approval by the U.S. Food and Drug Administration. Since 2006, almost 90 million doses of HPV vaccines have been administered nationally, and the most common side effects are soreness or swelling at the site of the shot.

Some parents think that “by giving the vaccine, you are saying it’s OK to have sex,” notes Keim-Malpass. Research doesn’t back this up. A 2012 study in Pediatrics of 11- to 12-year-old girls found that HPV vaccination was not tied to increased sexual activity, as measured by medical records of sexually-transmitted infection or pregnancy. A 2015 study in JAMA Internal Medicine of 12- to 18-year-old girls found no evidence to link HPV vaccination with higher rates of sexually transmitted infections.

The recommended age for vaccination ensures that preteens are protected before they are exposed to HPV, whenever that may be. “The whole reason the vaccine is targeted to 11- and 12-year-olds is to get kids vaccinated before they enter a sexual relationship,” says Keim-Malpass.

Lack of urgency is a problem, too. The delay between an infection and a future cancer can make people complacent about HPV. “You are protecting yourself from an infection, but it has ramifications years, decades later,” Keim-Malpass says. “It’s not about something you get tomorrow, it’s about something you could get 20 to 30 years from now.”

Another difficulty has been the vaccination schedule. The initial recommendation was for three doses, with the second shot one to two months after the first, and the third shot six months after the first. This schedule was challenging for busy adolescents, notes Keim-Malpass.

Now there is a new dosing regimen. For adolescents who begin vaccination before turning 15, only two shots are required, with the second one coming six to 12 months after the first. This should be easier to accommodate in yearly well-child visits.

Even with the suboptimal vaccination rates, there has been an impact on infections. A 2016 Pediatrics study found that, within six years of the first vaccine’s introduction in 2006, infections with the four HPV types covered decreased 64 percent among 14- to 19-year-old girls. There are also fewer cases of genital warts among U.S. teens since 2006.

Any decline in infection rates is a good thing. But “it’s not to the extent we could have, if from the get- go, people realized this was a cancer vaccine,” says Paskett. “If there was a vaccine for breast cancer, moms would be lining up around the corner with their daughters.”

Twisted textile cords may contain clues to Inca messages

Animal-hair cords dating to the late 1700s contain a writing system that might generate insights into how the Inca communicated, a new study suggests.

Researchers have long wondered whether some twisted and knotted cords from the Inca Empire, which ran from 1400 to 1532, represent a kind of writing about events and people. Many scholars suspect that these textile artifacts, known as khipus, mainly recorded decimal numbers in an accounting system. Yet Spanish colonial documents say that some Inca khipus contained messages that runners carried to various destinations.
Now a new twist in this knotty mystery comes from two late 18th century khipus stored in a wooden box at San Juan de Collata, a Peruvian village located high in the Andes Mountains. A total of 95 cord combinations of different colors, animal fibers and ply directions, identified among hundreds of hanging cords on these khipus, signify specific syllables, reports Sabine Hyland. Hyland, a social anthropologist at the University of St. Andrews in Scotland, describes the khipus online April 19 in Current Anthropology.

Her findings support a story told by Collata villagers that the khipus are sacred writings of two local chiefs concerning a late 18th century rebellion against Spanish authorities.

The Collata khipus display intriguing similarities to Inca khipus, including hanging cords with nearly the same proportions of two basic ply directions, Hyland says. A better understanding of Central Andean khipus from the 1700s through the 1900s will permit a reevaluation of the earlier Inca twisted cords, she suggests.

Each Collata khipu, like surviving Inca examples, consists of a horizontal cord from which a series of cords hang. One Collata specimen contains 288 hanging cords separated into nine groups by cloth ribbons tied at intervals along the top cord. The other khipu features 199 hanging cords divided by ribbons into four groups. Knots appear only at cord ends to prevent unraveling. In contrast, proposed accounting khipus contain many knots denoting numbers.

Collata khipus’ initial hanging cords are made of bundles of colored animal hairs that represent the message’s subject matter, Hyland proposes. One khipu starts with a tuft of bright red deer hair, followed by a woven, cone-shaped bundle with metallic-colored thread. The second khipu commences with a woven, tube-shaped bundle of multicolored alpaca hair atop the remains of a red tassel.
“The Collata khipus are completely unlike accounting khipus that I have been studying for over a decade,” Hyland says. Central Andean khipus generally viewed as accounting devices were often made of cotton, and they contain two main colors, between 15 and 39 cord combinations and repetitive knot sequences.

Hyland makes an “excellent case” that these cords represent syllables and probably words as well, says anthropological archaeologist Penelope Dransart of the University of Wales Trinity Saint David in Lampeter.

So far, Hyland has translated the final three cords on one khipu as the word Alluka, the name of a family lineage in Collata. She first talked to villagers and identified the lineage chief that they claimed wrote one of the khipus. Hyland then assigned the three syllables in Alluka to the trio of ending cords, assuming that the sender’s name would appear either there or at the beginning of the message. That enabled her to decipher the final cords on the second khipu as Yakapar, the name of a family lineage in a neighboring village. Heads of these lineages wrote the corded messages, Hyland suspects.

She has not yet deciphered other cords on the two khipus.

Hyland’s insights into 18th century khipus are “profoundly significant,” but won’t help to decipher Inca twisted and knotted cords, predicts Harvard University archaeologist Gary Urton. Collata villagers probably invented a phonetic form of khipu communication after the Inca civilization’s demise, when they were exposed to Spaniards’ alphabetic writing, Urton says. Inca khipus show no signs of cord combinations that corresponded to particular speech sounds, he asserts.

Thanks to the new discoveries, though, “we have hope that at least some khipus might be understood,” says archaeologist Jeffrey Splitstoser of George Washington University in Washington, D.C. Before Hyland’s report, Splitstoser thought it likely that colored threads on khipus had arbitrary meanings assigned by their makers, making them indecipherable. He studies khipus from the Wari empire, which flourished in the Peruvian Andes from around 600 to 1000 (SN: 5/10/03, p. 302).

Officials at several museums with khipu collections have classified as forgeries a few animal-hair specimens that resemble the Collata khipus, Hyland says. Those alleged fakes deserve a closer look for signs of writing, she contends.

Mummy DNA unveils the history of ancient Egyptian hookups

Egyptian mummies are back in style at the summer box office — and in genetics labs. A study of genetic blueprints from 90 mummies repairs the frayed reputation of sarcophagus occupants as sources of ancient DNA. And it reveals evidence of a hookup history with foreigners from the east.

An Egyptian mummy served up the first ancient human DNA sample in 1985 (SN: 4/27/85, p. 262). But both chemicals used in mummification and Egypt’s steamy climate can degrade DNA, and scientists weren’t sure if mummies could supply samples free of modern contamination.

Carefully screening for quality and using the latest in sequencing tech, Verena Schuenemann of the University of Tübingen in Germany and her colleagues extracted and analyzed mitochondrial DNA, which passes from mom to child. They worked primarily with samples from teeth and bones, rather than from soft tissue. Three mummies yielded readable samples of DNA from cell nuclei, which includes DNA from both parents. The mummies ranged in age of origin from 1388 B.C. to A.D. 426.

The analysis reveals genetic ties to the Middle East and Greece — not a huge surprise since Egypt was a center of travel and trade at that time. The conspicuous absence of genetic connections to sub-Saharan Africa seen in modern Egyptians points to a later influx of foreigners from that region, the researchers write May 30 in Nature Communications.

Launch your imagination with Science News stories

Imagine for a moment that you lived on another planet. Not Tatooine, Trantor or another fictional orb, but a real-deal planet circling a star somewhere in our real-deal galaxy. What would your world look like? Would there be a rocky surface? An atmosphere? How long would a day last? How about a year? What special physiology might you need to survive there? There’s no single scenario, of course. Starting with some basic facts, you can speculate in all sorts of surprising directions. That’s the fun of the exercise.

Over the last quarter century or so, astronomers have confirmed more than 3,600 exoplanets — that’s 3,600-plus worlds in addition to the planets, moons and other heavenly bodies known in our own solar system. People have long imagined what it would be like to live on Mars, and bold thinkers have dared to envision an existence on, say, Jupiter (see “Juno spacecraft reveals a more complex Jupiter“). Today there are many more possibilities, including planets orbiting dim red stars very different from our sun. In “Life might have a shot on planets orbiting dim red stars,” Christopher Crockett describes the hurdles life might face in evolving and surviving near these cool stars. On planets orbiting Proxima Centauri, TRAPPIST-1 and other M dwarfs, water could be extremely sparse, energetic flares might regularly singe the surface and you might live always in sun or forever in darkness.
Reading about these worlds, I’d say, is better than fiction — as is a lot of what Science News covers. You don’t need a novel or a movie to escape into what feels like another reality. Just flip through these pages. The stories will take you to other worlds, as well as inner, hidden ones. Former Science News intern Elizabeth S. Eaton writes about the bacteria that infect our bodies and the problem of antibiotic resistance. Picturing these invisible, single-celled organisms wreaking havoc in the body, unchecked by our best medicines, gives me goose bumps. Eaton’s story is about the battle that would ensue if predatory bacteria are sent in to hunt down and kill these bad guys, as some researchers have proposed. One researcher likens the bacteria to the antagonists in the Alien films. There’s true cinematic potential.

And it doesn’t end there. Bruce Bower takes readers into the past, to the roots of the human evolutionary tree. Most scientists think Africa was the birthplace of hominids, but new research suggests it could have been Europe. And Susan Milius offers an opportunity to consider what it might be like to live in another type of body — a flamingo’s. The birds have an off-kilter shape, with ankles where we’d expect knees. For flamingos, Milius reports, standing on one leg might be more stable than standing on two. After reading the story, I couldn’t help but attempt to balance on just my right foot, in hopes of getting a handle on human-flamingo differences. (It was an unsuccessful 20 seconds. Thank goodness my office door was closed.)

Every issue of Science News includes similar inspiration. There’s serious stuff to be sure, but there are plenty of chances to ponder the strangeness of reality — and to stretch it. After thinking about living on Proxima b or being a wading bird, consider being a wading bird on Proxima b. For fuel to help your imagination run, you’ve come to the right place.

This glass frog wears its heart for all to see

A newly discovered glass frog from Ecuador’s Amazon lowlands is giving researchers a window into its heart.

Hyalinobatrachium yaku has a belly so transparent that the heart, kidneys and urine bladder are clearly visible, an international team of researchers reports May 12 in ZooKeys. Researchers identified H. yaku as a new species using field observations, recordings of its distinct call and DNA analyses of museum and university specimens.

Yaku means “water” in Kichwa, a language spoken in Ecuador and parts of Peru where H. yaku may also live. Glass frogs, like most amphibians, depend on streams. Egg clutches dangle on the underside of leaves, then hatch, and the tadpoles drop into the water below. But the frogs are threatened by pollution and habitat destruction, the researchers write. Oil extraction, which occurs in about 70 percent of Ecuador’s Amazon rainforest, and expanding mining activities are both concerns.