NEWS AND NOTES ABOUT SCIENCE
CROWS LEARN MORE ABOUT TOOLMAKING
New Caledonian crows are known for their toolmaking, but Alex Taylor and his colleagues wanted to understand just how advanced they could be.
Crows from New Caledonia, an island in the South Pacific, can break off pieces of a branch to form a hook, using it to pull a grub out of a log, for instance. Once, in captivity, when a New Caledonian male crow had taken all the available hooks, its mate Betty took a straight piece of wire and bent it to make one.
“They are head and shoulders above almost every other avian subjects” at toolmaking, said Irene Pepperberg, an avian cognition expert and research associate in Harvard University’s department of psychology. “These crows are just amazing.”
Taylor, a researcher at the University of Auckland in New Zealand, and several European colleagues wondered how the crows, without an ability to talk and showing no evidence of mimicry, might learn such sophisticated toolmaking.
Perhaps, the scientists hypothesized in a new paper published in Scientific Reports, they used “mental template matching,” where they formed an image in their heads of tools they had seen used by others and then copied it.
“Could they look at a tool and just based on mental image of the tool — can they re-create that tool design?” Taylor said. “That’s what we set out to test, and that’s what our results show.”
In a series of steps, the researchers taught the birds to feed pieces of paper into a mock vending machine to earn food rewards. The scientists chose a task that was similar enough to something the animals do in the wild — while also brand-new. The birds had never seen card stock before, but learned how to rip it into big or little shapes after being shown they would get a reward for the appropriate size.
The template used to show the birds the right size of paper was not available to them when they made their “tools,” yet the crows were able to use their beaks to tear off bits of paper, which they sometimes held between their feet for leverage. Karen Weintraub
OWLS SEE THE WORLD MUCH LIKE WE DO
Owl eyes are round, but not spherical. These immobile, tubular structures sit on the front of an owl’s face like a pair of builtin binoculars. They allow the birds to focus in on prey and see in three dimensions, kind of like humans — except we don’t have to turn our whole heads to spot a slice of pizza beside us.
Although owls and humans both have binocular vision, it has been unclear whether these birds of prey process information they collect from their environments like humans, because their brains aren’t as complex. But in a study published recently in the Journal of Neuroscience, scientists tested the ability of barn owls to find a moving target among various shifting backgrounds, a visual processing task earlier tested only in primates.
The research suggests that barn owls, with far simpler brains than humans, also group together different elements as they move in the same direction, to make sense of the world around them.
“Humans are not so different from birds as you may think,” said Yoram Gutfreund, a neuroscientist at Technion Israel Institute of Technology, who led the study with colleagues from his university and RWTH Aachen University in Germany.
A critical part of perception is being able to distinguish an object from its background. One way humans do this is by grouping elements of a scene together to perceive each part as a whole. In some cases, that means combining objects that move similarly, like birds flying in a flock or the single bird that breaks away from it.
Scientists have generally considered this type of visual processing as a higher level task that requires complex brain structures. But Gutfreund and his team believed this ability was more basic — like seeing past camouflage.
They showed barn owls screens of black, moving dots on a gray background and attached cameras to their heads to track their gazes. Then the team measured how long it took the birds to turn their heads toward a target dot, moving in a different direction than numerous other shifting dots.
The owls were able to spot the target. Even though the elements were all black dots, the direction they were moving made a big difference in the owl’s perception
of the world — and how its brain responded. Joanna Klein
HIGH-RESOLUTION SNAPSHOT OF ZIKA VIRUS REVEALS CLUES TO FIGHTING IT
Scientists have captured the clearest and most detailed image yet of Zika, the virus that set off a global health crisis in 2015 and 2016 and left thousands of babies with serious birth defects. The work could contribute to the development of more effective vaccines and treatments to combat the virus.
The research, published recently in the journal Structure, combined tens of thousands of two-dimensional images to construct a three-dimensional model of the virus’ structure.
The team used electron microscopy, a technique that sends beams of electrons through a particle, projecting an image. The wavelengths of electrons — much shorter than that of light — are roughly the same as the distance between atoms, so scientists are able to perceive minute details.
“Previous studies didn’t hit this level of granularity,” said Dr. Peter Katona, an infectious disease specialist at the University of California, Los Angeles, who was not involved in the study.
The result is the highest-resolution image ever captured of a virus with an envelope, or protective outer shell. By visualizing the virus in such detail, the researchers may find pockets on its surface where the drug molecules could attach.
Such features may help scientists understand how vaccines and antiviral drugs could interact with Zika.
“A vaccine is a key that must fit perfectly into a virus’ lock,” Katona said. “The better we know the details of the lock, the better we can design the key.”
Zika is a flavivirus, a family that includes dengue and Japanese encephalitis, which are also transmitted by mosquitoes. A comparison with these viral relatives showed prominent differences at a specific region of Zika’s surface called the glycan loop.
That site might determine the type of cell that a virus infects — and in turn, the symptoms it would cause.
The study’s findings likely will not have an immediate effect on disease prevention, according to Kristian G. Andersen, a genomic researcher at the Scripps Research Institute. At present, many promising Zika vaccine candidates cannot be fully tested in humans because of a decline in infections. Bioethicists are conflicted over whether to allow testing in healthy people. Emily Baumgaertner
TOO FEW MR. RIGHTS LEAD MORE WOMEN TO FREEZE THEIR EGGS
Lots of women, many of them highly educated, have frozen their eggs in recent years. But the decision may have very little to do with work, at least according to a new study. In interviews with 150 American and Israeli women who had undergone one cycle, career planning came up as the primary factor exactly two times.
Instead, most women focused on another reason: They still had not found a man to build a family with.
“The stereotype that these ambitious career women are freezing their eggs for the purposes of their career; that’s really inaccurate at the present time,” said Marcia Inhorn, a medical anthropologist from Yale University, and one of the authors of the study.
Most of these mid-to-late 30s women were already established in their careers by the time they got to the clinic, the study found.
“They weren’t freezing to advance; they were facing the overarching problem of partnership,” she said. This was the case, even among those who worked for companies that offered to pay for the procedure.
The subjects in this particular study came from seven fertility clinics. In the United States, the women generally lived in cities along the East Coast or in the Bay Area. They ranged in age from 29 to 42, with three-quarters falling between 35 and 39.
Of the participating women, 85 percent were single and most were heterosexual. For about half of these single women, it was uncertainty about when they would meet a man to build a family with that brought them to the clinic, they told the researchers. The next largest group was driven there by a divorce or breakup. This was followed by a smaller group of women who were deployed overseas and felt it was wise to freeze their eggs first and then a handful of women who were preparing to have a baby on their own. Career planning was the least common reason.
One hypothesis that demographers often cite is that it is related to demographics. Women in many developed countries, including the United States, Canada, Britain, Japan, Norway and Australia are now more educated then men. This could be creating a dearth of appealing male partners for these women. Heather Murphy
MOVING MOLECULES, VIRTUALLY SPEAKING
There was a time when biochemists had a lot in common with sculptors. Scientists who had devoted their lives to studying a molecule would build a model, using metal and a forest of rods to hold up the structure of thousands of atoms. John Kendrew, who won the Nobel Prize in 1962 and was known for his model of myoglobin, said, “Slow work, but at the end you really know the molecule.”
These days simulations on screens have replaced Kendrewstyle models, sacrificing some of their tactile value while gaining the ability to show movement. But what if you could enter a virtual reality environment where the molecules lie before you, obeying all the laws of molecular physics as calculated by supercomputers, and move them around in three dimensions?
In a new paper in the journal Science Advances, researchers report that they have constructed just such an environment, and that users who manipulate the proteins in VR can perform simple tasks nearly 10 times faster in virtual reality than on a screen.
Where a molecule might bend, where it will not and just how the positive and negative charges it is riddled with attract and repel each other, are all key to understanding how a drug will slip into a cleft in a protein, among other puzzles.
In the virtual world, users are experiencing the cutting edge of what scientists know about how molecules move and flex, said David Glowacki, a researcher in chemistry and computer science at the University of Bristol in England who is a co-author of the paper. The simulation, which anyone with a virtual reality setup can access, is being run on Oracle supercomputers, with a grant from the company.
“When you reach out and touch these molecular strings, you are touching the absolute real physics,” Glowacki said. “The way that it moves and behaves is to the best of our knowledge the real deal.” Veronique Greenwood