NEWS AND NOTES ABOUT SCIENCE
WHY ONIONS MAKE YOU CRY
Trying to figure out why humans cry is exhausting. Onions make us teary because a reaction in the onion releases a chemical called lachrymatory factor, or LF, that irritates our eyes. The onion’s cells break open, allowing two normally separated substances to combine. Linked together like pieces of a puzzle, they become a potent chemical weapon.
“It turns into a gas. It hits your eyes, and then it hits your sensory nerves in your eyes and causes them to tear up,” said Josie Silvaroli, an undergraduate at Case Western Reserve University in Ohio who helped describe how these pieces fit together, structurally speaking, in a paper published in July in the journal ACS Chemical Biology. “It’s similar to tear gas.”
But is it possible to avoid the onion feelies?
In Japan, scientists engineered a tearless onion. But it lacks that signature onion flavor.
With regular onions, there are options: chuck your onion in the fridge before you cut it, or submerge it in water while chopping. Reducing the temperature will slow down the reaction, resulting in less LF.
Unfortunately, it seems there’s no simple way to avoid it. For the love of onions, sometimes you just have to cry. JOANNA KLEIN
STARTING FIRES TO UNEARTH HOW NEANDERTHALS MADE GLUE
Neanderthals seem stuck with unflattering reputations. The entire species of early human ancestors has long been reduced to a pejorative for describing someone who isn’t very bright, despite growing evidence of the sophistication of Homo neanderthalensis. And recent research suggests another overlooked mark of their ingenuity: They made the first glues in the form of tar.
The tar was distilled from the bark of birch trees some 200,000 years ago, and seemed to have been used for hafting, or attaching handles to stone tools and weapons. But scientists did not know how Neanderthals produced the dark, sticky substance.
Now, in a study published last Thursday in the journal Scientific Reports, a team of archaeologists has used materials available during prehistoric times to demonstrate three possible ways Neanderthals could have deliberately made tar. While the study does not prove that Neanderthals used any of these methods, it aims to demonstrate that they had access to the ingredients and means to produce tar.
“There’s this popular perspective of Neanderthals as being these simple cave men and slow-type brutes,” said Paul Kozowyk, a graduate student at Leiden University in the Netherlands and lead author of the study. “This tar production, and its use for hafting, is evidence that this isn’t really true.” NICHOLAS ST. FLEUR
WILD DOGS SNEEZE WHEN THEY ARE READY TO HUNT
When they want to move as a group, meerkats call to each other. Capuchin monkeys trill. Gorillas grunt. Honeybees make what is called a piping sound.
African wild dogs sneeze. And that’s a first.
For one thing it seems to indicate a positive reaction to a proposal before a group of dogs. When a pack of these dogs is getting ready to hunt, scientists reported Tuesday, the more sneezes, the more likely they are to actually get moving.
Just about all social organisms make group decisions that require reaching a consensus. Bacteria use chemical signals but larger animals often use sounds as a way of saying, I’m in. However, among grunts, huffs, piping signals and others, the sneeze had not been reported as one of those signals until a group of American, British and Australian researchers published their observations of African dogs in the Proceedings of the Royal Society B.
Unlike the oneperson, one-vote rules of human elections, members of the group were not limited to one sneeze. And if a dominant pack member started a rally, fewer sneezes were needed from the other dogs to get the hunt off the ground, one researcher said. JAMES GORMAN
SATELLITE IMAGES OF NORTH KOREA SHOW LANDSLIDES AT NUCLEAR TEST SITE
Analysts peering at satellite images of North Korea after the latest nuclear test reported that they had spotted many landslides and wide disturbances at the country’s test site, in the North’s mountainous wilds. Tunnels for the nuclear blasts are deep inside Mount Mantap, a mile-high peak.
“These disturbances are more numerous and widespread than what we have seen from any of the five tests North Korea previously conducted,” three experts wrote in an analysis for 38 North, a website run by the U.S.-Korea Institute of the Johns Hopkins University School of Advanced International Studies.
The new satellite images of the Punggye-ri nuclear test site
were taken Monday, the day after the nuclear detonation. Planet, a company in San Francisco that owns swarms of tiny satellites, reconnoitered the secretive nuclear test site.
The three analysts — Frank V. Pabian, Joseph S. Bermudez Jr., and Jack Liu — said the wide disturbances appeared to include numerous landslides throughout the rugged site “and beyond.”
They added that they could find no evidence of a surface crater that would have formed if the cavern carved out within the mountain by the blast’s violence and high temperatures had suddenly collapsed. WILLIAM J. BROAD
WHY BATS CRASH INTO BUILDINGS
Bat echolocation is a finely tuned sense. By emitting highfrequency calls and listening for returning echoes, bats can deftly navigate complex surroundings and precisely target moving prey in the dark. But this extraordinary capability is not foolproof. A study published Thursday in Science reveals a weak spot in bat echolocation: smooth, vertical surfaces such as the metal or glass plates on buildings can trick a bat into thinking it is flying in open air. The findings may help explain why the creatures are often found dead or injured near buildings and other smooth structures, said Stefan Greif, an author of the study and a postdoctoral researcher affiliated with the Max Planck Institute for Ornithology in Germany and Tel Aviv University in Israel.
When a bat approaches a smooth, vertical surface from an angle — as it would when turning a corner in a rectangular tunnel — its echolocating calls mostly reflect away from it. It’s not until a bat gets very close to a flat, vertical surface that some of its calls end up hitting the plate at a 90-degree angle and bouncing right back. At this point, Greif and his collaborators noted, bats tended to change their echolocation patterns, shortening the time between calls, to collect more information. But it was often too late — out of 78 instances they observed of bats coming close to a vertical plate, 25 resulted in near misses while 53 resulted in crashes. STEPH YIN