Photograph by FEORD ET AL., 2020
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Scientists study the cephalopods’ 3D vision (when the animals keep the glasses on).
Photograph by FEORD ET AL., 2020

Cuttlefish glasses, counting strings, and other novel tools

These objects of research—whether recently invented or centuries old—may yield new insights into civilizations, aeronautics, and life sciences.

This story appears in the June 2020 issue of National Geographic magazine.

A new dimension to cuttlefish’s hunting

Cool as a … cuttlefish? The shades on this species are more than stylish: They revealed to scientists that cuttlefish, like humans, see with stereopsis, or two-eyed depth perception. When shown computer images of two shrimps—one red, one blue—placed slightly apart on a screen, the trained invertebrates moved close enough each time to sling their tentacles at the digital prey. This meant that the cuttlefish were calculating depth within seconds, their brains merging the red and blue shrimp images into a single 3D picture. Figuring out another animal’s location in the water is vital for European cuttlefish to catch speedy prey, says University of Minnesota ecologist Trevor Wardill. “There’s a lot more going on in that head than you might guess,” he says. Still, the research hit snags. At first the cephalopods, like petulant tots, pulled off the glasses—until scientists plied them with treats: live shrimps. —Christine Dell'Amore

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Why did scientists outfit cuttlefish with 3D glasses? To study how the cephalopods target prey using stereopsis, or two-eyed depth perception.

The need for speed—but with less noise

As supersonic T-38 jets flew over the California Mojave Desert, their shock waves merged. Cameras on a NASA airplane 2,000 feet above captured the image—and data that may help quiet the sonic booms of future supersonic aircraft. —Michael Greshko

Honoring how Inca kept records

Because the Inca Empire lacked alphabetic writing, bureaucrats made notes with a quipu, a tool of colored strings and knots. Researchers studying 1,000 or so surviving quipus say they likely were used to record census data, taxes, and stories about Inca rulers. In January the Peruvian Ministry of Culture gave the quipu national heritage status, hailing it as an ingenious legacy of the indigenous culture. —Nina Strochlic

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With this tool made of colored and knotted strings, bureaucrats of the Inca Empire kept track of important information, such as census data and taxes.

Magnetic heart passes test

At least 26 million people worldwide suffer heart failure; only about 5,500 a year get transplants. Artificial hearts so far have been heavy and complex—but a new “maglev heart” (below), powered by a single, magnetically levitating disk, could be a solution. Tested successfully in cows, the palm-size titanium device will soon begin human trials. —CD

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This new artificial heart, tested successfully in cows, is powered by a magnetically levitating disk.