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It’s not the size of a snake’s muscles that matter, but how it uses them. King snakes can defeat larger snakes in a wrestling match to the death because of how they coil around their prey, researchers report March 15 in the Journal of Experimental Biology.

King snakes wrap around their food and squeeze with about twice as much pressure as rat snakes do, says David Penning, a functional morphologist at Missouri Southern State University in Joplin. Penning, along with colleague Brad Moon at the University of Louisiana at Lafayette, measured the constriction capabilities of almost 200 snakes. “King snakes are just little brutes,” Penning says.
King snakes, which are common in North American forests and grasslands, are constrictor snakes that “wrestle for a living,” Penning says. They mainly eat rodents, birds and eggs, squeezing so hard, they can stop their prey’s heart (SN: 8/22/15, p. 4). In addition, about a quarter of the king snake diet is other snakes. King snakes can easily attack and eat vipers because they’re immune to the venom, but when they take on larger constrictors, such as rat snakes, it has been unclear what gives them the edge. “That’s not how nature goes,” Penning says, because predators are usually larger than their prey.

King snakes, though, can eat snakes up to 35 percent larger than themselves. One of the largest king snake conquests on record, from 1893, is of a 5-foot-3-inch rat snake, about 17 percent larger than the 4-foot-6-inch king snake that consumed it, Penning says.
“David Penning is really one of the first researchers that has been looking at the anatomy, physiology and function of these snakes” to understand how king snakes are superior to rat snakes, says Anthony Herrel, a functional morphologist and evolutionary biologist at the French National Museum of Natural History in Paris.
To determine what makes these snakes kings, Penning and Moon compared their muscle size, ability to escape attack and the strength of their squeeze to that of rat snakes. In one test, the researchers shook dead rodents enticingly in front of the snakes to goad them into striking and squeezing. Sensors on the rodents recorded the pressure of the squeeze.

The king snakes constricted with an average pressure of about 20 kilopascals, stronger than the pumping pressure of a human heart. Rat snakes in the same tests applied only about 10 kilopascals of pressure.

But the king snakes weren’t bigger body builders. Controlling for body size, the two kinds of snakes “had the exact same quantity of muscle,” Penning says.

The snakes’ more powerful constriction is probably due to how they use their muscles, not how much muscle they have, the researchers conclude. They observed that the majority of king snakes in the study wrapped around their food like a spring in what Penning calls the “curly fry pattern.” Rat snakes didn’t always coil in the same way and often ended up looking like a “weird pile of spaghetti,” he says.

Penning plans to study how other factors influence constriction as well, such as how long the king snakes can squeeze, how hungry they are and the temperature of their environment.

I’ve been to the playground enough times to know a juicy parenting controversy when I see (or overhear) one. Bed-sharing, breastfeeding and screen time are always hot-button issues. But I’m not talking about any of those. No, I’m talking about actual juice.

Some parents see juice as a delicious way to get vitamins into little kids. Others see juice as a gateway drug to a sugar-crusted, sedentary lifestyle, wrapped up in a kid-friendly box. No matter where you fall on the juice spectrum, you can be sure there are parents to either side of you. (Disclosure: My kids don’t drink much juice, simply because the people who buy their groceries aren’t all that into it. And juice is heavy.)

Scientific studies on the effects of juice have been somewhat sparse, allowing deeply held juice opinions to run free. One of the chief charges against juice is that it’s packed with sugar. An 8-ounce serving of grape juice, even with no sugar added, weighs in at 36 grams. That tops Coca-Cola, which delivers 26 grams of sugar in 8 ounces. And all of those extra sweet calories can lead to extra weight.

A recent review of eight studies on juice and children’s body weight, published online March 23 in Pediatrics, takes a look at this weight concern. It attempts to clarify whether kids who drink 100 percent fruit juice every day are at greater risk of gaining weight. After sifting through the studies’ data, researchers arrived at an answer that will please pro-juicers: Not really.

“Our study did not find evidence that consuming one serving per day of 100 percent fruit juice influenced BMI to a clinically important degree,” says study coauthor Brandon Auerbach of the University of Washington in Seattle.

The analysis found that for children ages 1 to 6, one daily serving of juice (6 to 8 ounces) was associated with a sliver of an increase in body mass index, or BMI. Consider a 5-year-old girl who started out right on the 50th percentile for weight and BMI. After a year of daily juice, this girl’s BMI may have moved from the 50th to the 52nd or 54th percentile, corresponding to a weight increase of 0.18 to 0.33 pounds over the year. That amount “isn’t trivial, but it’s not enough on its own to lead to poor health,” Auerbach says.

The results, of course, aren’t the final word. The analysis was reviewing data from other studies, and those studies came with their own limitations. For one thing, the studies didn’t assign children to receive or not receive juice. Instead, researchers measured the children’s juice-drinking behavior that was already under way and tried to relate that to their weight. That approach means that it’s possible that differences other than juice consumption could influence the results.
It’s important to note the distinction here between the 100 percent fruit juice in the studies and fruit cocktails, which are fruit-flavored drinks that often come with lots of added sugar. The data on those drinks is more damning in terms of weight gain and the risk of cavities, Auerbach says.

Also worth noting: The American Academy of Pediatrics recommends that kids between ages 1 and 6 get only 4 to 6 ounces of juice a day. That’s a smaller amount than many of the kids in the studies received. And the AAP recommends babies younger than 6 months get no juice at all.

In general, whole fruits, such as apples and oranges, are better than juice because they provide fiber and other nutrients absent from juice. (Bonus for toddlers: Oranges are fun to peel. Bummer for parents: Doing so makes a sticky mess.)

Still, the new analysis may ease some guilt around letting the juice flow. And it can enable parents to save their worries for more harmful things, of which there are plenty.

Like 1980s hair bands, male cockatoos woo females with flamboyant tresses and killer drum solos.

Male palm cockatoos (Probosciger aterrimus) in northern Australia refashion sticks and seedpods into tools that the animals use to bang against trees as part of an elaborate visual and auditory display designed to seduce females. These beats aren’t random, but truly rhythmic, researchers report online June 28 in Science Advances. Aside from humans, the birds are the only known animals to craft drumsticks and rock out.
“Palm cockatoos seem to have their own internalized notion of a regular beat, and that has become an important part of the display from males to females,” says Robert Heinsohn, an evolutionary biologist at the Australian National University in Canberra. In addition to drumming, mating displays entail fluffed up head crests, blushing red cheek feathers and vocalizations. A female mates only every two years, so the male engages in such grand gestures to convince her to put her eggs in his hollow tree nest.

Heinsohn and colleagues recorded more than 131 tree-tapping performances from 18 male palm cockatoos in rainforests on the Cape York Peninsula in northern Australia. Each had his own drumming signature. Some tapped faster or slower and added their own flourishes. But the beats were evenly spaced — meaning they constituted a rhythm rather than random noise.

From bonobos to sea lions, other species have shown a propensity for learning and recognizing beats. And chimps drum with their hands and feet, sometimes incorporating trees and stones, but they lack a regular beat.

The closest analogs to cockatoo drummers are human ones, Heinsohn says, though humans typically generate beats as part of a group rather than as soloists. Still, the similarity hints at the universal appeal of a solid beat that may underlie music’s origins.

Quantum particles can burrow through barriers that should be impenetrable — but they don’t do it instantaneously, a new experiment suggests.

The process, known as quantum tunneling, takes place extremely quickly, making it difficult to confirm whether it takes any time at all. Now, in a study of electrons escaping from their atoms, scientists have pinpointed how long the particles take to tunnel out: around 100 attoseconds, or 100 billionths of a billionth of a second, researchers report July 14 in Physical Review Letters.
In quantum tunneling, a particle passes through a barrier despite not having enough energy to cross it. It’s as if someone rolled a ball up a hill but didn’t give it a hard enough push to reach the top, and yet somehow the ball tunneled through to the other side.

Although scientists knew that particles could tunnel, until now, “it was not really clear how that happens, or what, precisely, the particle does,” says physicist Christoph Keitel of the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. Theoretical physicists have long debated between two possible options. In one model, the particle appears immediately on the other side of the barrier, with no initial momentum. In the other, the particle takes time to pass through, and it exits the tunnel with some momentum already built up.

Keitel and colleagues tested quantum tunneling by blasting argon and krypton gas with laser pulses. Normally, the pull of an atom’s positively charged nucleus keeps electrons tightly bound, creating an electromagnetic barrier to their escape. But, given a jolt from a laser, electrons can break free. That jolt weakens the electromagnetic barrier just enough that electrons can leave, but only by tunneling.

Although the scientists weren’t able to measure the tunneling time directly, they set up their experiment so that the angle at which the electrons flew away from the atom would reveal which of the two theories was correct. The laser’s light was circularly polarized — its electromagnetic waves rotated in time, changing the direction of the waves’ wiggles. If the electron escaped immediately, the laser would push it in one particular direction. But if tunneling took time, the laser’s direction would have rotated by the time the electron escaped, so the particle would be pushed in a different direction.

Comparing argon and krypton let the scientists cancel out experimental errors, leading to a more sensitive measurement that was able to distinguish between the two theories. The data matched predictions based on the theory that tunneling takes time.
The conclusion jibes with some physicists’ expectations. “I’m pretty sure that the tunneling time cannot be instantaneous, because at the end, in physics, nothing can be instantaneous,” says physicist Ursula Keller of ETH Zurich. The result, she says, agrees with an earlier experiment carried out by her team.

Other scientists still think instantaneous tunneling is possible. Physicist Olga Smirnova of the Max Born Institute in Berlin notes that Keitel and colleagues’ conclusions contradict previous research. In theoretical calculations of tunneling in very simple systems, Smirnova and colleagues found no evidence of tunneling time. The complexity of the atoms studied in the new experiment may have led to the discrepancy, Smirnova says. Still, the experiment is “very accurate and done with great care.”

Although quantum tunneling may seem an esoteric concept, scientists have harnessed it for practical purposes. Scanning tunneling microscopes, for instance, use tunneling electrons to image individual atoms. For such an important fundamental process, Keller says, physicists really have to be certain they understand it. “I don’t think we can close the chapter on the discussion yet,” she says.

THE WOODLANDS, Texas — Mars’ missing magnetic field may have drowned in the planet’s core.

An excess of hydrogen, split off from water molecules and stored in the Martian mantle, could have shut down convection, switching the magnetic field off forever, planetary scientist Joseph O’Rourke proposed March 21 at the Lunar and Planetary Science Conference.

Planetary scientists think magnetic fields are produced by the churning of a planet’s molten iron core. Convection relies on denser materials sinking into the core, and lighter stuff rising to the surface. The movement of iron, which can carry a charge, generates a strong magnetic field that can protect a planet’s atmosphere from being ravaged by solar wind (SN Online: 8/18/17).
But if lighter material, like hydrogen, settles close to the iron core, it could block dense material from sinking deep enough to keep convection going, said O’Rourke, of Arizona State University in Tempe.

“Too much hydrogen and you can shut down convection entirely,” he said. “Hydrogen is a heartless killer.”

O’Rourke and his ASU colleague S.-H. Dan Shim suggested the hydrogen could come from water locked up in Martian minerals. Near the hot core, water would split into hydrogen and oxygen. The oxygen would form compounds with other elements and stay high in the mantle, but the hydrogen could sit atop the core and effectively suffocate the dynamo.
The question is whether Mars’ minerals would have had what it took to deliver the hydrogen at the right time. Mars’ crust is rich in the mineral olivine, which does not bond well with water and so is relatively dry.

In the planet’s interior, pressure forces olivine to transform into the minerals wadsleyite and ringwoodite, which hold more water. Deeper still, the mineral turns into bridgmanite and becomes dry again. For a time, that bridgmanite layer could act as a buffer against water, allowing the core to keep convecting. But as the mantle cooled, the bridgmanite layer would shrink and eventually disappear, O’Rourke’s study suggests.

Whether Mars’ interior ever had that saving layer of bridgmanite depends on how big its core is — a property that may be tested by NASA’s InSight Mars lander, launching on May 5, O’Rourke said. Mars did have a magnetic field more than 4 billion years ago. Scientists have struggled to explain how it vanished, leaving the planet vulnerable to solar winds, which probably stripped away its atmosphere and surface water (SN: 12/12/15, p. 31).

If hydrogen shut down the planet’s generator, it would have had to act fast. Previous observations suggest the magnetic field disappeared relatively rapidly, over 100 million years.

Another theory by James Roberts of the Johns Hopkins Applied Physics Lab in Laurel, Md., suggests a large impact could have shut down the dynamo by heating the outermost core, which would have kept it from sinking.

“It’s actually a similar idea to O’Rourke’s,” Roberts says. It may take many more sophisticated Mars missions to figure out what really happened.

Honeybee royal jelly is food meant to be eaten on the ceiling. And it might also be glue that keeps a royal baby in an upside-down cradle.

These bees raise their queens in cells that can stay open at the bottom for days. A big blob of royal jelly, abundantly resupplied by worker bees, surrounds the larva at the ceiling. Before the food is deposited in the cell, it receives a last-minute jolt of acidity that triggers its proteins to thicken into goo, says Anja Buttstedt, a protein biochemist at Technische Universität Dresden in Germany. Basic larva-gripping tests suggest the jelly’s protein chemistry helps keep future queens from dropping out of their cells, Buttstedt and colleagues propose March 15 in Current Biology.
Suspecting the stickiness of royal jelly might serve some function, researchers tweaked its acidity. They then filled small cups with royal jelly with different pH levels and gently turned the cups upside down. At a natural royal jelly acidity of about pH 4.0, all 10 larvae dangled from their gooey blobs upside down overnight. But in jelly boosted to pH 4.8 (and thinned in the process), four of the 10 larvae dropped from the cups. At pH 5.9, all of them dropped.

Honeybees build several forms of royally oversized cells for raising a queen. Those for queens who will swarm with their workers to a new home hang from the rim of an array of regular cells. A hole stays open at the bottom of the cell until the larva nears pupation from her fat grub shape into a queen with wings. That hole at the bottom is big enough for a royal larva to fall through, confirms insect physiologist Steven Cook at the honeybee research lab in Beltsville, Md., run by the U.S. Department of Agriculture’s Agricultural Research Service.

Buttstedt and colleagues propose that the stickiness of royal jelly may be what keeps the larva in place. The team worked out how the jelly’s proteins change as it is made, and how those changes affect its consistency.

Royal jelly is secreted as a brew of proteins from the glands above a worker bee’s brain. At that point, it has a neutral pH, around 7, like water’s. The worker bee then adds fatty acids from glands in her mouthparts, which take the pH to around 4.
“It has a quite sour smell,” Buttstedt says. As for taste? “Really weird.” A steady diet of this jelly is what turns a larvae into a queen instead of a worker.

At pH 4, the jelly’s most common protein, MRJP1, goes complicated. When the protein leaves the glands above the brain, it’s clustered in groups of four along with smaller proteins called apisimins, the team found. When the acidity shifts, the MRJP1 foursomes and the apisimins hook together in slender fibers and get gluey.

“The most puzzling question,” Buttstedt says, is “why build upside-down queen cells in the first place?”

Delusional infestation
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A deep conviction that one’s skin is contaminated with insects or other objects despite a lack of medical evidence.

She was certain her skin was infested: Insects were jumping off; fibers were poking out. Fearful her condition could spread to others, the 50-year-old patient told doctors at the Mayo Clinic in Rochester, Minn., that she was avoiding contact with her children and friends.

The patient had delusional infestation, explains Mayo Clinic dermatologist Mark Davis. Sufferers have an unshaking belief that pathogens or inanimate objects pollute their skin despite no medical evidence. Davis and colleagues report online April 4 in JAMA Dermatology that the disorder is not as rare as previously assumed.
In the first population-based study of the disorder’s prevalence, the researchers identified 35 cases from 1976 to 2010 reported in Minnesota’s Olmsted County. Based on the findings, the authors estimate 27 out of every 100,000 people in the United States have delusional infestation. Due to the county’s lack of diversity — the population of about 150,000 is predominantly white — the researchers used only the nationwide white population to estimate prevalence, so the result may not be representative of other populations.

Delusional infestation has been recognized for decades, albeit under different names. Patients insist they’ve been overtaken with creatures, such as insects, worms or parasites, or inanimate materials like fibers — or both.
“It’s like aliens have infested their skin,” Davis says. Some present bagged samples of the claimed culprits, which turn out to be such debris as sand, dander or, as in the case of the 50-year-old woman, bits of skin and scabs. When lab tests confirm no infestation, patients often seek another opinion rather than accept the findings. Some attempt risky self-treatments, such as bathing in kerosene or bleach, or tweezing or cutting the skin.

Schizophrenia, dementia or other psychiatric illnesses can trigger delusional infestation. So can such drugs as amphetamines or cocaine. But when no other illness is involved, patients often reject the notion that the issue is psychiatric and tend to refuse the antipsychotic medications that can help, Davis says.

As for the 50-year-old patient, upset with the doctors’ diagnosis, she no longer comes to the Mayo Clinic.

Scientists playing peekaboo with dark matter have entered a new stage of the game.

For the first time, physicists are snooping on some of the likeliest hiding places for hypothetical subatomic particles called axions, which could make up dark matter. So far, no traces of the particles have been found, scientists with the Axion Dark Matter Experiment, ADMX, report April 9 in Physical Review Letters. But the researchers have now shown that their equipment is sensitive enough to begin searching in earnest.

An ethereal substance that makes up much of the matter in the universe, dark matter is necessary to explain the motions of stars within galaxies, among other observations. Scientists don’t know what dark matter is, but axions, extremely lightweight particles that may permeate the cosmos, are one of the major contenders.

Most past searches for dark matter particles have focused on a different candidate particle, known as a weakly interacting massive particle, or WIMP. But those efforts have so far come up empty (SN: 11/12/16, p. 14). Now, the spotlight is on the underdog axions.
“We have to make sure we are considering all the possibilities,” says theoretical physicist Matthew Buckley of Rutgers University in Piscataway, N.J., who was not involved with the new result. Axions, he says, are a plausible candidate for dark matter.

Axions would produce incredibly feeble signals, so pinning down evidence for the minuscule particles is no easy undertaking. But ADMX, located at the University of Washington in Seattle, is now up to the task, says ADMX member Aaron Chou, a physicist at Fermilab in Batavia, Ill. Previous experiments have searched for axions, but those efforts weren’t sensitive enough to have a good chance of detecting the particles.

“It’s an experimental tour de force; it’s amazing work,” says theoretical physicist Helen Quinn of SLAC National Accelerator Laboratory in Menlo Park, Calif., who was not involved with the research.

ADMX uses what is essentially a supersensitive radio, isolated from external sources of radio waves and cooled to temperatures near absolute zero (‒273.15° Celsius). Scientists use the apparatus to search for axions converting into radio waves in a strong magnetic field. If axions exist, they are expected to interact with photons, particles of light, from the magnetic field. In the process, they would produce radio waves at a frequency that depends on the axion’s mass, which is unknown. Like scanning the dial for a good oldies station, scientists will gradually change the frequency at which they search, trying to “listen in” on the axion signal.

While the new study came up empty, scientists scanned only a small range of frequencies, ruling out some possible masses for axions, from 2.66 to 2.81 microelectron volts. Those tiny masses are less than a billionth of an electron’s mass. In the future, ADMX will study other possible masses. “There’ll be a lot of excitement in the next few years,” Chou says. “A discovery could come at any time.”

Using the precise position and brightness of almost 1.7 billion stars, the Gaia spacecraft has created the most precise 3-D map of the Milky Way yet.

On April 25, the European Space Agency’s Gaia team released the spacecraft’s second batch of data, gathered from July 2014 to May 2016, used to create the map. The tally includes measurements of half a million quasars — the active black holes at the centers of distant galaxies — and 14,099 known solar system objects (mostly asteroids), observations of other nearby galaxies and the amount of dust in between Earth and 87 million stars (SN: 4/14/18, p. 27).The spacecraft also measures the distances and motions of stars by taking advantage of Earth’s motion around the sun, a technique called parallax. As Earth moves, stars appear to trace a small ellipse, whose size is related to the stars’ distance. Measuring the wavelengths of light the stars emit tells how fast they are moving toward or away from the sun. Combining Gaia’s measurements with earlier sky surveys let astronomers track stars’ motions.

Gaia launched in 2013, and released its first batch of data in September 2016 (SN: 10/15/16, p. 16). Those data included distances and motions of roughly 2 million stars; the new data up that number to 1.3 billion.

Knowing those distances will allow astronomers to decipher details about the Milky Way’s shape and history. Already the second data release suggests that the galaxy contains two distinct populations of stars that may have different origins. The stars’ chemistry and motions suggest that some could have originated in a different galaxy that the Milky Way cannibalized long ago.

“With Gaia, we can reconstruct the whole history of the Milky Way,” ESA science director Günther Hasinger said in a news conference April 25.

In Finland, 88 percent of people have a genetic variation that increases their risk for migraines. But in people of Nigerian descent, that number drops to 5 percent.

Coincidence? Maybe. But a new study suggests that, thousands of years ago, that particular genetic mutation increased in frequency in northern populations because it somehow made people better suited to handle cold temperatures. That change may have had the unfortunate consequence of raising the prevalence of these severe headaches in certain populations, researchers report May 3 in PLOS Genetics.
The mutation is in a stretch of DNA that controls the behavior of TRPM8, a protein that responds to cold sensation. People with the older version of this DNA snippet seems less susceptible to migraines than people with the mutated version, previous studies have shown.

Using a global database of human genetic information, evolutionary geneticist Aida Andres and her colleagues showed a correlation between the frequency of the mutation in a given population and that population’s latitude. It’s rare in Africa, for example, but fairly common across Europe.

Differences in temperature may have led to this variation, though scientists still aren’t sure exactly how the mutation affects TRPM8. Perhaps the mutation conferred some benefit to early humans who moved north from Africa, says Andres, of University College London. The connection to migraine appears to be a side effect.

The researchers acknowledge, however, that the science of migraines isn’t so simple. One variant can’t fully explain why these headaches are more common in certain populations. Migraine risk is “very complex,” Andres says. “It’s highly heritable, but other things impact it, too.”
Plus, there’s still a lot to learn about TRPM8. “We don’t even really know how the entirely normal [protein], with no mutations, contributes to migraine,” says Greg Dussor, a neurobiologist at the University of Texas at Dallas who wasn’t part of the study.

Even the link between migraine and temperature is muddy: While cold temperatures can trigger migraines in some people, heat sets others off.