There's something odd about turtle-headed sea snakes. It is not their name, or that they give live birth instead of laying eggs, or that they paddle more than they slither. It's their skin. For years, researchers noticed that the aquatic snakes living in waters near human activity had jet-black skin, but most others, in more pristine waters, were speckled or banded.
But now, in a recent report published in Current Biology, scientists suggest that the varied coloration of sea snakes is probably an adaptation that helps them deal with pollution. It is like the moths in Europe that swapped speckled for black wings during the Industrial Revolution, evading hungry birds by blending in with coal dust. Only, rather than camouflage, black sea snake skin may act more like a pollution trap collecting heavy metals absorbed by the snakes and then cleaning them out as the skin is shed.
Researchers tested the shed skins of black and banded sea snakes for more than a dozen trace minerals, including zinc, arsenic, cobalt and nickel. As expected, the black skin — whether it belonged to a whole black snake or just a black band — contained more of the metals.
Trying to figure out the evolutionary advantage of this correlation, the researchers determined that it was not camouflage. They reasoned that the minerals accumulated in the water, moved up the food chain and became sequestered in the black skin. The dark skin also attracted an algae, which took residence on the snakes' bodies, creating a heavy, velvety cloak. To get rid of the algae, which slowed them down in the water, the snakes shed their skin more often, protecting them from levels of metals that are toxic in other animals.
Joanna Klein, New York Times
Why it seems like North Korea is launching missiles all the time now
North Korea shot a ballistic missile over Japan last week, a provocation coming directly on the heels of a three-missile test days earlier. If it seems like these launches are happening all the time now, there's a good reason for that. "North Korea is testing its missiles faster than I can update the page," said Shea Cotton, a research associate at the Center for Nonproliferation Studies who maintains a database of launches.
Current ruler Kim Jong Un has overseen a surge in missile testing following his ascension in 2011. In 2017 alone, for instance, North Korea has conducted at least 18 missile tests. That's more than the 16 tests conducted during the entire 17-year reign of his father, Kim Jong Il. In the past four years, North Korea has launched nearly twice as many missiles (76) as it did in the three preceding decades (39).
Just as significant as the number and type of missiles launched, is the rapid increase in the number of launch sites. Kim Jong Un's predecessors conducted missile tests at just two sites each, according to the Center for Nonproliferation Studies. But under Kim, missiles have been launched from at least 17 sites across the country.
"The strategic importance of this shift is immense," writes the Center for Nonproliferation Studies. The group's analysts believe that the country is launching missiles from numerous locations in order to give its military forces, deployed across the country, experience in handling the weapons in the event of a conflict.
Christopher Ingraham, Washington Post
Trying to match the face? Don't look at the hair
Matching up photos of strangers' faces is surprisingly difficult, and the average person is likely to be duped by matching hairstyles. These are two key findings from a study in the Journal of Experimental Psychology: Applied. The findings gained additional relevance as people across the Internet rushed to expose — or "doxx" — the identities of participants in the white nationalist rally in Charlottesville, Va.
The case of an engineering professor in Arkansas who was incorrectly identified as a torch-wielding marcher seems to illustrate this point. "It seems rather easy. You have a picture of a person and you just have to tell whether it's the same person or not," Benedikt Wirth, a researcher in the Department of Psychology at the Saarland University who studies facial processing abilities, said in an interview. "But our research and previous research shows this is a really demanding task, and there's a lot of error." The study showed that the average person is likely to be duped by matching hairstyes, and the face-matching can be difficult even for experienced police officers.
Heather Murphy, New York Times
Savor the moment. Take a picture.
A study in Psychological Science found that taking photos during an experience helped people remember visuals more accurately, even when they did not revisit their photos.
However, snapping pictures also appeared to decrease how much spoken information people retained.
Researchers asked people to walk through a museum exhibit while listening to an audio guide, and either take photos freely or leave their phones and cameras outside.
Afterward, when given a memory test, those who took pictures better recalled objects they had seen, but were less able to remember facts from the audio guide, than those who did not take pictures.
Focusing on visuals pulls our attention away from other senses, like hearing, said Alix Barasch, one of the authors and an assistant professor at the New York University Stern School of Business.
The findings suggest the process of looking around for what to photograph "actually causes you to encode visual content and remember it," Barasch said.
Steph Yin, New York Times
When are you really random? After age 24
The ability to behave randomly can be a great asset. Think of the mouse trying to outrun a cat — moving in an erratic, unpredictable way makes it harder to catch. In humans, this sort of behavior is thought to be linked to creativity and cognitive complexity. But understanding the mind's capacity to produce randomness is difficult.
Recently, a team from Europe pitted humans and computers against one another in a series of tasks designed to measure random choice-making. Around age 25, the researchers determined, people are best able to produce a random result. Their results were published in PLOS Computational Biology.
Measuring how participants performed against several factors, including age, sex and educational background, the researchers found a strong trend only with age. On average, performance improved from childhood to the mid 20s. It then stayed relatively high until the 60s, after which it began to decline.
For those older than 60, though, there was no need to fret. Not only was the difference between participants ages 25 and those ages 60 relatively small, but there are probably other trade-offs influencing creative capacity. For instance, one researcher said, "You may be less able to produce randomness but have much more experience to draw from."
Steph Yin, New York Times
Bone's marks suggest a cannibal ritual in ancient Britain
When Silvia Bello gives lectures about cannibalism, she starts by asking her audience to imagine a cannibal. "Normally, people think of Hannibal Lecter or something that's disturbing," said Bello, an anthropologist at the Natural History Museum in London.
But archaeological evidence suggests that most cannibalism in human history was not the work of serial killers. Instead, it occurred for complex and varied reasons. Thousands of years ago in Britain, for example, people seem to have eaten their own kind as part of an intricate funeral custom that combined both nutrition and ritual. At an archaeological site called Gough's Cave, in southwestern England, human bones that are about 15,000 years old bear unmistakable signs of cannibalism, like butchering marks and human tooth imprints that suggest even the ends of toe and rib bones were gnawed to get at every last bit of grease and marrow. But the bones also seem to have been used in cultural traditions. In a paper published in PLOS One, Bello said it is possible that people practiced cannibalism as a way to dispose of, or even honor, the dead. In this context, engraving the bone might have been a way to extend a memory of the deceased before the body was broken down and eaten.
Steph Yin, New York Times