Why Rudolph’s Shiny Red Nose Makes Scientific Sense

Certain Christmas legends require a suspension of disbelief, but a new paper published by Frontiers for Young Minds ("science edited for kids, by kids") reveals that Rudolph’s iconic red nose isn’t one of them—at least not entirely.

Dartmouth College anthropologist and evolutionary biologist Nathaniel J. Dominy here delves into the unique characteristics of Rangifer tarandus tarandus—specifically, how their eyes are well-suited to winter navigation. Unlike humans and most other mammals, Arctic reindeer are able to see ultraviolet light, which is a useful trait to have during those months of the year when the Sun is low on the horizon and light is scattered high in the atmosphere, making it UV and blue-purplish.

Additionally, reindeer have reflective tissue in their eyes that changes color with the seasons. Golden in the summer, the tissue turns to deep blue in the winter, which is believed to help the animals see blue light. The tissue also improves their ability to see in the dark and makes their eyes shine at night.

So, if reindeer basically have superhero sight, couldn't any random reindeer lead Santa's sleigh? Nope. The problem is fog. As you’ll recall, in Robert L. May’s original story, it was a foggy Christmas Eve when Santa came to say: “Rudolph with your nose so bright / won’t you guide my sleigh tonight?” Reindeer are hindered by the fog, which makes purple and blue light practically invisible. Red light, on the other hand, travels well in fog and would be extremely helpful for guiding an airborne sleigh with a planet’s worth of presents. Rudolph’s luminescent snout would be a perfect solution. The final optical benefit comes with the specific red of the nose, which is compared in one version of the story to the color of holly berries. That level of red is quite possibly the maximum redness that the eyes of mammals are able to see. In other words, Rudolph’s nose is perfectly engineered for the task at hand.

There is one small problem. Reindeer noses are vascular, which means they lose a lot of body heat through their schnozzes. Rudolph with his nose so bright might be prone to excessive heat loss, with a risk for hypothermia. The good news, writes Dominy, is that we can do something to help: "It is therefore extremely important for children to provide high-calorie foods to help Rudolph maintain his body temperature on Christmas Eve.”

You heard him. Prepare your plates of milk and cookies accordingly.

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How Bats Protect Rare Books at This Portuguese Library
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Visit the Joanina Library at the University of Coimbra in Portugal at night and you might think the building has a bat problem. It's true that common pipistrelle bats live there, occupying the space behind the bookshelves by day and swooping beneath the arched ceilings and in and out of windows once the sun goes down, but they're not a problem. As Smithsonian reports, the bats play a vital role in preserving the institution's manuscripts, so librarians are in no hurry to get rid of them.

The bats that live in the library don't damage the books and, because they're nocturnal, they usually don't bother the human guests. The much bigger danger to the collection is the insect population. Many bug species are known to gnaw on paper, which could be disastrous for the library's rare items that date from before the 19th century. The bats act as a natural form of pest control: At night, they feast on the insects that would otherwise feast on library books.

The Joanina Library is famous for being one of the most architecturally stunning libraries on earth. It was constructed before 1725, but when exactly the bats arrived is unknown. Librarians can say for sure they've been flapping around the halls since at least the 1800s.

Though bats have no reason to go after the materials, there is one threat they pose to the interior: falling feces. Librarians protect against this by covering their 18th-century tables with fabric made from animal skin at night and cleaning the floors of guano every morning.

[h/t Smithsonian]

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Honey Bees Can Understand the Concept of Zero
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The concept of zero—less than one, nothing, nada—is deceptively complex. The first placeholder zero dates back to around 300 BCE, and the notion didn’t make its way to Western Europe until the 12th century. It takes children until preschool to wrap their brains around the concept. But scientists in Australia recently discovered a new animal capable of understanding zero: the honey bee. According to Vox, a new study finds that the insects can be taught the concept of nothing.

A few other animals can understand zero, according to current research. Dolphins, parrots, and monkeys can all understand the difference between something and nothing, but honey bees are the first insects proven to be able to do it.

The new study, published in the journal Science, finds that honey bees can rank quantities based on “greater than” and “less than,” and can understand that nothing is less than one.

Left: A photo of a bee choosing between images with black dots on them. Right: an illustration of a bee choosing the image with fewer dots
© Scarlett Howard & Aurore Avarguès-Weber

The researchers trained bees to identify images in the lab that showed the fewest number of elements (in this case, dots). If they chose the image with the fewest circles from a set, they received sweetened water, whereas if they chose another image, they received bitter quinine.

Once the insects got that concept down, the researchers introduced another challenge: The bees had to choose between a blank image and one with dots on it. More than 60 percent of the time, the insects were successfully able to extrapolate that if they needed to choose the fewest dots between an image with a few dots and an image with no dots at all, no dots was the correct answer. They could grasp the concept that nothing can still be a numerical quantity.

It’s not entirely surprising that bees are capable of such feats of intelligence. We already know that they can count, teach each other skills, communicate via the “waggle dance,” and think abstractly. This is just more evidence that bees are strikingly intelligent creatures, despite the fact that their insect brains look nothing like our own.

Considering how far apart bees and primates are on the evolutionary tree, and how different their brains are from ours—they have fewer than 1 million neurons, while we have about 86 billion—this finding raises a lot of new questions about the neural basis of understanding numbers, and will no doubt lead to further research on how the brain processes concepts like zero.

[h/t Vox]

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