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Surrounded by Death on Snake Island

Dan Lewis runs the popular daily newsletter Now I Know (“Learn Something New Every Day, By Email”). To subscribe to his daily email, click here.

Off the coast of Sao Paolo, Brazil, sits Ilha de Quimada Grande or, as it's known colloquially in English, "Snake Island." The island, roughly 110 acres of trees, is uninhabited. Travel to the island is expressly forbidden by the Brazilian navy. Why? Because Queimada Grande is home to hundreds of thousands of golden lanceheads, the snake pictured at left.

Golden lanceheads are unique to Queimada Grande. The snake typically grows to be about two feet long, but in some cases can be nearly double that length. And its venom is poisonous. Very, very poisonous.

Lanceheads (that is, the more common cousins of the golden lancehead) are responsible for 90% of snake bite-related fatalities in Brazil. The mortality rate from a lancehead bite is 7% if the wound goes untreated, and can be as high as 3% even if treatment is given. The venom causes a grab bag of symptoms, including kidney failure, necrosis of muscular tissue, brain hemorrhaging, and intestinal bleeding.

For Snake Island, the picture is even scarier. The data above does not include bites from the golden lancehead, as there are no official records of a golden lancehead-caused fatality due to the de facto quarantine on their island. A chemical analysis of golden lancehead venom, though, suggests that the snake is much, much more dangerous than its continental cousins: Golden lancehead venom is faster acting and more powerful — perhaps five times more powerful.

Getting close to a two-foot snake with such powerful venom carries with it a high risk of death. And getting close to one is all but certain on Snake Island. Even the most conservative estimate suggests that the golden lancehead population density on Queimada Grande is one per square meter; others suggest a population as high as five per square meter. Regardless, as Atlas Obscura points out, even at the lower estimate, "you're never more than three feet away from death."

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Wisconsin Department of Natural Resources
Why Is Ice Slippery?
Wisconsin Department of Natural Resources
Wisconsin Department of Natural Resources

If you’ve ever shakily stepped onto the ice at your local skating rink, you are intimately familiar with the fear of falling on slippery ice. But what makes ice so slippery in the first place? Interestingly enough, scientists are still trying to figure that one out.

Physicists used to believe that ice became slippery when it was exposed to applied pressure. This pressure, they theorized, lowered the melting temperature of the top layer of ice. They believed that when a person went ice skating, the pressure from the blade caused the topmost layer of ice to melt. The thin layer of water allowed the ice skate to glide easily over the surface. After the blade passed, the top layer of water refroze.

However, most scientists today claim that this theory is wrong. “Ice is a very mysterious solid,” Robert M. Rosenberg, a chemistry professor at Lawrence University, said in an interview with The New York Times.

Scientists found that while pressure does lower the melting point of ice, it only does so by a fraction of a degree. Instead, they proposed that the friction from an ice skate causes the ice to melt beneath it.

Others believe that ice naturally possesses a fluid layer comprised of unstable water molecules. While these molecules search for stability, they move chaotically over the ice’s surface and create a slippery layer.

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Determining Migratory Patterns of Early Humans — With Earwax!

Dan Lewis runs the popular daily newsletter Now I Know (“Learn Something New Every Day, By Email”). To subscribe to his daily email, click here.

Earwax is mostly gross, but it serves a few purposes: protecting our ear canals from bacteria and dryness, assisting in cleaning and lubrication, and — surprisingly — helping anthropologists determine the migratory patterns of early humans.

While most native English speakers have wet, amber-to-brown colored earwax, there's a second type — dry, gray, and flaky. Which type of earwax you have is determined genetically, with the dry type being recessive and perhaps the result of a genetic mutation somewhere along the way. For some reason, the mutation is common among East Asians. An estimated 97 to 100 percent of people of European and African descent have the wet-type earwax, while 90 percent or more of those descended from East Asians have the dry type.

The gene that controls the relative wetness of earwax is tied to sweat, generally, and the prevailing belief amongst researchers is that the recessive gene, insofar that it reduces sweat output, had advantages in the colder climates of northern China (where, along with Korea, dry earwax is most common), where the mutation seems to have begun.

But for the rest of the world population, earwax makeup is mixed. Native Americans and people from southeast Asia, for example, exhibit dry earwax in 30 to 50 percent of the population, and it appears to occur more densely in some communities thereof than others. Armed with this information, researchers can determine in part the ancestral routes of different people and how those ancestors got to where their descendants now live.
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BONUS FACT: Whales' earwax increases over time without (mostly) discharging. This makes the amount of earwax in a whale's ear proportional to its age. As many whales (for example, baleen whales such as the blue whale, the world's largest mammal) do not have teeth, earwax buildup is one of the best ways to determine how old the whale is. For toothed whales and dolphins? Their teeth grow in layers and, much like the rings of a tree's trunk, the layers are used to determine the animal's age.

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