Aside from being adorable, sea otters and Indo-Pacific bottlenose dolphins share an ecological feat: Both species use tools. Otters crack open snails with rocks, and dolphins carry cone-shaped sponges to protect their snouts while scavenging for rock dwelling fish.

Researchers have linked tool use in dolphins to a set of differences in mitochondrial DNA — which passes from mother to offspring — suggesting that tool-use behavior may be inherited. Biologist Katherine Ralls of the Smithsonian Institution in Washington, D.C., and her colleagues looked for a similar pattern in otters off the California coast. The team tracked diet (primarily abalone, crab, mussels, clams, urchins or snails) and tool use in the wild and analyzed DNA from 197 individual otters.

Otters that ate lots of hard-shelled snails — and used tools most frequently — rarely shared a common pattern in mitochondrial DNA, nor were they more closely related to other tool-users than any other otter in the population.

Unlike dolphins, sea otters may all be predisposed to using tools because their ancestors probably lived off mollusks, which required cracking open. However, modern otters only take up tools when their diet requires them, the researchers report March 21 in Biology Letters.

SAN FRANCISCO — When faced with simple math problems, people who get jittery about the subject may rely more heavily on certain brain circuitry than math-savvy people do. The different mental approach could help explain why people with math anxiety struggle on more complicated problems, researchers reported March 25 at the Cognitive Neuroscience Society’s annual meeting.

While in fMRI machines, adults with and without math anxiety evaluated whether simple arithmetic problems, such as 9+2=11, were correct or incorrect. Both groups had similar response times and accuracy on the problems, but brain scans turned up differences.

Specifically, in people who weren’t anxious about math, lower activation of the frontoparietal attention network was linked to better performance. That brain network is involved in working memory and problem solving. Math-anxious people showed no correlation between performance and frontoparietal network activity.

People who used the circuit less were probably getting ahead by automating simple arithmetic, said Hyesang Chang, a cognitive neuroscientist at the University of Chicago. Because math-anxious people showed more variable brain activity overall, Chang speculated that they might instead be using a variety of computationally demanding strategies. This scattershot approach works fine for simple math, she said, but might get maxed out when the math is more challenging.

Could fluorescence matter to a frog? Carlos Taboada wondered. They don’t have bedroom black lights, but their glow may still be about the night moves.

Taboada’s question is new to herpetology. No one had shown fluorescence in amphibians, or in any land vertebrate except parrots, until he and colleagues recently tested South American polka dot tree frogs. Under white light, male and female Hypsiboas punctatus frogs have translucent skin speckled with dark dots. But when the researchers spotlighted the frogs with an ultraviolet flashlight, the animals glowed blue-green. The intensity of the glow was “shocking,” says Taboada of the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” in Buenos Aires.
And it is true fluorescence. Compounds in the frogs’ skin and lymph absorb the energy of shorter UV wavelengths and release it in longer wavelengths, the researchers report online March 13 in Proceedings of the National Academy of Sciences. But why bother, without a black bulb? Based on what he knows about a related tree frog’s vision, Taboada suggests that faint nocturnal light is enough to make the frogs more visible to their own kind. When twilight or moonlight reflects from their skin, the fluorescence accounts for 18 to 30 percent of light emanating from the frog, the researchers calculate.
Polka dot frogs, common in the Amazon Basin, have plenty to see in the tangled greenery where they breed. Males stake out multilevel territories in vast floating tangles of water hyacinths and other aquatic plants. When a territory holder spots a poaching male, frog grappling and wrestling ensues. Taboada can identify a distinctive short treble bleat “like the cry of a baby,” he says, indicating a frog fight.
Males discovering a female give a different call, which Taboada could not be coaxed to imitate over Skype. The polka dot frogs’ courtship is “complex and beautiful,” he says. For instance, a male has two kinds of secretion glands on the head and throat. During an embrace, he nudges and presses his alluring throat close to a female’s nose. If she breaks off the encounter, he goes back to clambering in rough figure eights among his hyacinths, patrolling for perhaps the blue-green ghost of another chance.

A stellar game of chicken between two young stars about 500 years ago has produced some fantastic celestial fireworks, new images released on April 7 by the European Southern Observatory reveal.

Whether or not the stellar duo collided is unclear. But their close encounter sent hundreds of streamers of gas, dust and other young stars shooting into space like an exploding firecracker. Using the Atacama Large Millimeter/submillimeter Array in Chile, John Bally of the University of Colorado Boulder and colleagues made the first measurements of the velocities of carbon monoxide gas in the streamers. From the data, they identified the spot where the stars probably interacted and determined that the encounter ripped apart the stellar nursery in which the stars were born. Such a cataclysmic event flung nursery debris into space at speeds faster than 540,000 kilometers an hour.

The dueling stars were born in a stellar nursery called Orion Molecular Core 1, about 1,500 light-years from Earth behind the Orion Nebula. There, gas weighing 100 suns collapses under its own gravity, making the material dense enough for embryotic stars to take shape. Gravity can pull those stellar seeds toward each other, with some grazing or colliding with each other and violently erupting. In this case, the encounter produced a kick as powerful as the energy the sun emits over 10 million years.

This explosion may have initially released a burst of infrared light lasting years to decades. If so, such spars among young stars might explain mysterious infrared flashes observed in other galaxies, the scientists suggest.

Earth’s magnetic field helps eels go with the flow.

The Gulf Stream fast-tracks young European eels from their birthplace in the Sargasso Sea to the European rivers where they grow up. Eels can sense changes in Earth’s magnetic field to find those highways in a featureless expanse of ocean — even if it means swimming away from their ultimate destination at first, researchers report in the April 13 Current Biology.

European eels (Anguilla anguilla) mate and lay eggs in the salty waters of the Sargasso Sea, a seaweed-rich region in the North Atlantic Ocean. But the fish spend most of their adult lives living in freshwater rivers and estuaries in Europe and North Africa.
Exactly how eels make their journey from seawater to freshwater has baffled scientists for more than a century, says Nathan Putman, a biologist with the National Oceanic and Atmospheric Administration in Miami.

The critters are hard to track. “They’re elusive,” says study coauthor Lewis Naisbett-Jones, a biologist now at the University of North Carolina at Chapel Hill. “They migrate at night and at depth. The only reason we know they spawn in the Sargasso Sea is because that’s where the smallest larvae have been collected.”

Some other marine animals, like sea turtles and salmon, tune in to subtle changes in Earth’s magnetic field to help them migrate long distances. To test whether eels might have the same ability, Putman and his colleagues placed young European eels in a 3,000-liter tank of saltwater surrounded by copper wires. Running electric current through the wires simulated the magnetic field experienced at different places on Earth.
With no electric current, the eels didn’t swim in any particular direction. But when the magnetic field matched what eels would experience in the Sargasso Sea, the fish mostly swam to the southwest corner of their tank. That suggests the eels might use the magnetic field as a guide to help them move in a specific direction to leave their spawning grounds.

Swimming southwest from the Sargasso Sea seems counterintuitive for an eel trying to ultimately go northeast, Putman says. But computer simulations revealed that that particular bearing would push eels into the Gulf Stream, whisking them off to Europe. Catching a more circuitous ride on a current is probably more efficient for the eels than swimming directly across the North Atlantic, says Putman.

Magnetic fields could help eels stay the course, too. A magnetic field corresponding to a spot in the North Atlantic further along the eels’ route to Europe sent the eels in the tank heading northeast. That’s the direction they’d need to go to keep following the Gulf Stream to Europe.

The researchers did see a fair amount of variation in how strongly individual eels responded to magnetic fields. But that makes sense, says Julian Dodson, a biologist at Laval University in Quebec City who wasn’t part of the study. The Gulf Stream is such a powerful current that the eels could wriggle in a spread of directions to get swept up in its flow.

Now, the researchers are looking at whether adult eels use a similar magnetic map to get back to the Sargasso Sea. Adults follow a meandering return route that might take more than a year to complete, previous research suggests (SN Online: 10/5/16). But whether there’s some underlying force that guides them remains to be seen.

Lab coats aren’t typical garb for mass demonstrations, but they may be on full display April 22. That’s when thousands of scientists, science advocates and science-friendly citizens are expected to flood the streets in the March for Science. Billed by organizers as both a celebration of science and part of a movement to defend science’s vital role in society, the event will include rallies and demonstrations in Washington, D.C., and more than 400 other cities around the world.

“Unprecedented,” says sociologist Kelly Moore, an expert on the intersection of science and politics at Loyola University Chicago. “This is the first time in American history where scientists have taken to the streets to collectively protest the government’s misuse and rejection of scientific expertise.”

Some scientists have expressed concern that marching coats science in a partisan sheen; others say that cat is long out of the bag. Keeping science nonpartisan is a laudable goal, but scientists are human beings who work and live in societies — and have opinions as scientists and citizens when it comes to the use, or perceived misuse, of science.

Typically when scientists get involved with a political issue, it’s as an expert sharing knowledge that can aid in creating informed policy. There are standard venues for this: Professional societies review evidence and make statements about a particular issue, researchers publish findings or consensus statements in reports or journals, and sometimes scientists testify before Congress.

In extreme circumstances, though, scientists have embraced other forms of activism. To broadly categorize, there are:

Celebrity voices
In 1938, amid the rise of fascism and use of false scientific claims to support the racism embedded in Nazism, prominent German-American anthropologist Franz Boas released his “Scientists Manifesto.” Signed by nearly 1,300 scientists, including three Nobel laureates, the manifesto denounced the unscientific tenets of Nazism and condemned fascist attacks on scientific freedom.
Fear of war of a different sort prompted Albert Einstein, Bertrand Russell and nine other scientists to compose a manifesto in 1955 calling for nuclear disarmament. The Russell-Einstein Manifesto led to the first Pugwash Conference on Science and World Affairs, which sought “a world free of nuclear weapons and other weapons of mass destruction.”
Wildlife biologist Rachel Carson eloquently synthesized research on the effects of pesticides in her wildly popular book Silent Spring, published in 1962 (she would later testify before Congress). Despite attacks from industry and some in government, Carson’s work helped launch the modern environmental movement, paving the way for the establishment of the Environmental Protection Agency.

Advocacy groups
In the 1930s, chapters of the American Association of Scientific Workers (based loosely on a similar British organization) formed in various cities including Philadelphia, Boston and Chicago. Despite broad goals — promoting science for the benefit of society, stressing public science education, taking a moral stand against government and industry misuse of science — infighting and members’ opposing views limited the group’s effectiveness.

In the decades since, other broadly focused groups — for example, Science for the People (born out of a group started in 1969 by physicists frustrated by their professional society’s lack of action against the Vietnam War), the Union of Concerned Scientists, the American Association for the Advancement of Science — have picked up the banner, speaking out, circulating petitions and more. Single-issue groups such as the Environmental Defense Fund and the Council for Responsible Genetics have proliferated as well.

Protest marchers
Many scientists have traded pocket protectors for placards, hitting the streets as concerned scientist-citizens. Academic scientists frequently joined university students in rallies against the Vietnam War in the 1960s and early ’70s. Linus Pauling famously protested nuclear testing in a march outside the White House in 1962 (he was in town for a dinner with the Kennedys honoring Nobel laureates). Carl Sagan was one of hundreds arrested for protesting nuclear testing at a Nevada site in 1987. And plenty of scientist-citizens joined the inaugural Women’s March on Washington in January and the annual People’s Climate March (the 2017 one is scheduled for April 29, just a week after the March for Science).

But the March for Science feels different, say the science historians. Transforming concern into sign-toting, pavement-pounding, slogan-shouting activism is motivated by a collective — and growing — sense of outrage that the federal government is undermining, ignoring, even discarding and stifling science. That’s hitting many scientists not just in their livelihoods, but in the very fabric of their DNA. “Part of [President] Trump’s message is that science is not going to be thought of as part of a collective good that’s essential for decision making in a democracy,” Moore says. “We have not seen this outright rejection of science by the state.”

That rejection has come in many forms, says David Kaiser, a science historian at MIT. “It’s a cluster of issues: cutbacks in basic research across many domains, the censure and censorship regarding data collected by the government or the ability of government scientists to speak, and a range of threats to academic freedom and the research process generally.”

It’s a sign of the times, too, says Al Teich, a science policy expert at George Washington University in Washington, D.C. President Reagan, for example, slashed science in his budget in 1981. But many more people today are aware of science’s role in society, says Teich, the former director for science and policy programs at AAAS. This awareness may be fueling the upcoming march. “The number of people engaged and the range of scientists involved is not something that I’ve ever seen before.”

Measuring the impact of any of these efforts is difficult. They aren’t controlled laboratory experiments, after all. But one thing this march may do is spawn a new form of activism, says Moore: more scientists running for political office.

Mooching roommates are an ancient problem. Certain species of beetles evolved to live with and leech off social insects such as ants and termites as long ago as the mid-Cretaceous, two new beetle fossils suggest. The finds date the behavior, called social parasitism, to almost 50 million years earlier than previously thought.

Ants and termites are eusocial — they live in communal groups, sharing labor and collectively raising their young. The freeloading beetles turn that social nature to their advantage. They snack on their hosts’ larvae and use their tunnels for protection, while giving nothing in return.

Previous fossils have suggested that this social parasitism has been going on for about 52 million years. But the new finds push that date way back. The specimens, preserved in 99-million-year-old Burmese amber, would have evolved relatively shortly after eusociality is thought to have popped up.

One beetle, Mesosymbion compactus, was reported in Nature Communications in December 2016. A different group of researchers described the other, Cretotrichopsenius burmiticus, in Current Biology on April 13. Both species have shielded heads and teardrop-shaped bodies, similar to modern termite-mound trespassers. Those adaptations aren’t just for looks. Like a roommate who’s found his leftovers filched one too many times, termites frequently turn against their pilfering housemates.

Smarty-pants have 40 new reasons to thank their parents for their powerful brains. By sifting through the genetics of nearly 80,000 people, researchers have uncovered 40 genes that may make certain people smarter. That brings the total number of suspected “intelligence genes” to 52.

Combined, these genetic attributes explain only a very small amount of overall smarts, or lack thereof, researchers write online May 22 in Nature Genetics. But studying these genes, many of which play roles in brain cell development, may ultimately help scientists understand how intelligence is built into brains.
Historically, intelligence research has been mired in controversy, says neuroscientist Richard Haier of the University of California, Irvine. Scientists disagreed on whether intelligence could actually be measured and if so, whether genes had anything at all to do with the trait, as opposed to education and other life experiences. But now “we are so many light-years beyond that, as you can see from studies like this,” says Haier. “This is very exciting and very positive news.”

The results were possible only because of the gigantic number of people studied, says study coauthor Danielle Posthuma, a geneticist at VU University Amsterdam. She and colleagues combined data from 13 earlier studies on intelligence, some published and some unpublished. Posthuma and her team looked for links between intelligence scores, measured in different ways in the studies, and variations held in the genetic instruction books of 78,308 children and adults. Called a genome-wide association study or GWAS, the method looks for signs that certain quirks in people’s genomes are related to a trait.

This technique pointed out particular versions of 22 genes, half of which were not previously known to have a role in intellectual ability. A different technique identified 30 more intelligence genes, only one of which had been previously found. Many of the 40 genes newly linked to intelligence are thought to help with brain cell development. The SHANK3 gene, for instance, helps nerve cells connect to partners.

Together, the genetic variants identified in the GWAS account for only about 5 percent of individual differences in intelligence, the authors estimate. That means that the results, if confirmed, would explain only a very small part of why some people are more intelligent than others. The gene versions identified in the paper are “accounting for so little of the variance that they’re not telling us much of anything,” says differential developmental psychologist Wendy Johnson of the University of Edinburgh.

Still, knowing more about the genetics of intelligence might ultimately point out ways to enhance the trait, an upgrade that would help people at both the high and low ends of the curve, Haier says. “If we understand what goes wrong in the brain, we might be able to intervene,” he says. “Wouldn’t it be nice if we were all just a little bit smarter?”

Posthuma, however, sees many roadblocks. Beyond ethical and technical concerns, basic brain biology is incredibly intricate. Single genes have many jobs. So changing one gene might have many unanticipated effects. Before scientists could change genes to increase intelligence, they’d need to know everything about the entire process, Posthuma says. Tweaking genetics to boost intelligence “would be very tricky.”

Lots of newborn decorations come in black and white, so that young babies can better see the shapes. But just because it’s easier for babies to see bold blacks and whites doesn’t mean they can’t see color.

Very few studies of color vision in newborns exist, says Anna Franklin, a color researcher at the University of Sussex in England. “But those that have been conducted suggest that newborns can see some color, even if their color vision is limited,” she says. Newborns may not be great at distinguishing maroon from scarlet, but they can certainly see a vivid red.

But as babies get a little older, they get remarkably adept at discerning the world’s palette, new research shows. Babies ages 4 months to 6 months old are able to sort colors into five categories, researchers report in the May 23 Proceedings of the National Academy of Sciences.

These preverbal color capabilities offer insight into something scientists have long wondered: Without words for individual colors, how do babies divvy up the hues across the color wheel, telling when blue turns to green, for instance?

Along with Franklin and colleagues, psychologist Alice Skelton, also of the University of Sussex, bravely approached this question. The team coaxed 179 4- to 6-month-old babies to calmly and repeatedly look at two squares, each 1 of 14 various colors.

After showing babies two squares of the same color over and over, the researchers made one of the squares a new color. Gazing at the new hue longer was a sign that the baby recognized the color as new. In this meticulous way, the researchers worked their way around the entire color wheel for each baby.

The experiment required stamina, from both Skelton and the young participants. “Sometimes you can have whole weeks where the babies just don’t want to do it,” she says. Despite that, she found the process enjoyable: “Babies are nice people.”
Babies, like adults, bin hues into red, yellow, green, blue and purple, Skelton and her colleagues found. “Given the commonalities and patterns you see in the way that languages divide up the color spectrum, we did expect that we would see some evidence of these same patterns in the way babies divide up the spectrum,” Skelton says. “What was surprising, for me at least, was how nicely it fell out.”

That discernment comes even though the babies probably don’t know the words for the colors. This suggests that babies are most likely born with these categories preprogrammed in their brains. The babies in the study came from just one culture. But “we anticipate that infants from different cultures would categorize color similarly,” Franklin says.

The results offer an interesting window into what’s happening in a baby’s brain as she learns about her world. And the results also come with a gentle suggestion: Don’t restrict your newborn’s art to black and white. She may already harbor a fondness for blue.

Acting like miniature trees that soak up sunlight and release oxygen, photosynthetic bacteria injected into the heart may lighten the damage from heart attacks, a new study in rats suggests.

When researchers injected the bacteria into rats’ hearts, the microbes restored oxygen to heart tissue after blood supply was cut off as in a heart attack, researchers at Stanford University report June 14 in Science Advances.

“It’s really out of the box,” says Himadri Pakrasi, a systems biologist at Washington University in St. Louis who was not involved in the research. “It reads like science fiction to me, but it’s fantastic if it works.”
The organism, called Synechococcus elongatus, has been used recently to produce biofuels, but this may be the first time the cyanobacteria have ever been used in a medical setting, he says.

Other researchers also reacted enthusiastically to the study. “It’s outrageous, but outrageous in a good way,” says Susan Golden, who studies cyanobacteria at the University of California, San Diego. Cardiovascular scientist Matthias Nahrendorf of Massachusetts General Hospital in Boston says, “I enjoy the idea. It’s really fresh.”

Bringing oxygen to starved tissues is what Stanford cardiovascular surgeon Joseph Woo had in mind when he and colleagues dreamed up the plan to put light-harvesting bacteria into the heart. In a heart attack, clogged arteries or blood clots cut off blood flow to the organ. Without oxygen supplied by the blood, heart cells die.

Woo wanted a way for the heart to make its own oxygen or access another supply until doctors could open blocked vessels and restore blood flow. Plants make oxygen from carbon dioxide and sunlight, so Woo wondered, “Why not bring the tree to your heart?”

He and colleagues started by grinding up kale and spinach to harvest chloroplasts, the organelles within plant cells that carry out photosynthesis. But the chloroplasts didn’t survive outside the cells. That’s when the researchers learned about S. elongatus, a photosynthetic organism that Golden and other researchers have long used to study circadian rhythms.
After finding that cyanobacteria could provide oxygen to heart cells in a lab dish, the next step was to see how the cyanobacteria would fare in an animal. The researchers stopped blood flow to part of rats’ hearts and after 15 minutes injected either cyanobacteria or a saline solution. Oxygen in tissue with bacteria increased to about three times the levels measured right after the heart attack, similar to what saline-treated rats experienced.
That was in the dark: When researchers exposed the heart to light, rats that got the bacteria had 25 times higher oxygen levels than they did after the heart attack. Four weeks after the treatment, these rats had less heart damage than untreated rodents, indicating long-term benefits. In fact, the hearts of photosynthesis-treated rats were beating strongly: Blood flow out of the heart was 30 percent higher in rats treated with cyanobacteria and light than those treated with the bacteria in the dark. That extra blood flow could make the difference between life and death for some patients, Woo says. The results indicate that the bacteria need light to supply heart cells with enough oxygen to stave off damage. That presents a difficulty if the cyanobacteria are ever to be used in people: Getting light into the heart is a major hurdle.

“It will be next to impossible to open the chest to light,” says Nahrendorf. “A day on the beach won’t do the trick.” Woo says the researchers are working with engineers at Stanford to make devices that can shine light through bones and skin to reach the heart and other deep tissues.

Injecting bacteria into the heart is also a risky proposition. “What you’re doing is infecting a tissue, and that’s rarely a good thing,” says Nahrendorf. But the cyanobacteria were cleared from the rats’ bodies within 24 hours and didn’t provoke the immune system to attack the heart, the researchers found. Some other cyanobacteria produce toxins, says Golden. “But this organism is benign,” she says.

Cyanobacteria might also supply oxygen to tissues in other diseases, such as brain injuries, strokes or nonhealing wounds in people with diabetes, says Arnar Geirsson, a cardiovascular scientist at Yale University. Photosynthetic bacteria might also help preserve organs for transplant.

“I’m quite impressed,” Geirsson says. “It’s a really unique way to deliver oxygen.”