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Newcastle University

Scientists Create Tiny 3D Glasses for Mantises

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Newcastle University

If the female African mantis (Sphodromantis lineola) pictured above wearing teensy 3D glasses looks like she’s on her way to the movies, that’s because she is. But it wasn’t just insect dress-up time in the laboratory. The minuscule specs and movie theater were an experiment to find out if mantises can see in three dimensions.

The idea of not being able to see 3D sounds pretty weird, but scientists say stereoscopic, or 3D, vision is actually pretty rare in the animal kingdom. Humans have it (most humans, anyway), as do other primates, horses, birds, cats, and toads. However, it’s generally believed that invertebrates like bugs see the world in only two dimensions. To date, only one invertebrate has been shown to possess stereoscopic vision: the praying mantis. 

The original mantis vision experiment occurred in the 1980s. At the time, the researcher was pretty limited in the 3D images he could create. More than 20 years later, 3D technology is everywhere, and a team of researchers figured they could build a pretty decent mantis movie theater. For science.

Scientists Vivek Nityananda, Ghaith Tarawneh, Ronny Rosner, Judith Nicolas, Stuart Crichton, and Jenny Read outlined their methods and findings in a paper published yesterday in Scientific Reports. The first step was to make a movie that would interest a mantis audience. They opted for an animation of a spiraling disc against a brightly colored background. The disc bounced around the screen, occasionally hovering in place—a bug-like movement pattern that has been shown to keep the mantises’ attention and even provoked them to strike. They set the animation to play on a high-resolution computer monitor and constructed a small black tunnel to limit the size of the screen. 

Next, they cut out little circles from blue and green plastic filters. They stuck the mantises briefly in a freezer to sedate them, then pulled them out and affixed the 3D glasses to their faces with beeswax and rosin. Looking like extras in a B-52s video, the mantises then went back to their cages to recover from the weirdness they’d just experienced.

 

Image credit: Newcastle University

The next day, the researchers took out the newly bespectacled bugs and brought them to the little movie theater. They set them in front of the tunnel and recorded how many times the mantises tried to strike the images they saw on the screen.

The results confirm the mantises’ use of 3D vision. When the target was rendered in three dimensions and seemed to pop off the screen, the mantises lunged for it. When it was 2D, they didn’t show much interest.

The research team was pleased with their results. "Despite their minute brains, mantises are sophisticated visual hunters which can capture prey with terrifying efficiency,” lead researcher Jenny Reed said in a press statement. “We can learn a lot by studying how they perceive the world.” 

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Big Questions
Why Do Cats Freak Out After Pooping?
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iStock

Cats often exhibit some very peculiar behavior, from getting into deadly combat situations with their own tail to pouncing on unsuspecting humans. Among their most curious habits: running from their litter box like a greyhound after moving their bowels. Are they running from their own fecal matter? Has waste elimination prompted a sense of euphoria?

Experts—if anyone is said to qualify as an expert in post-poop moods—aren’t exactly sure, but they’ve presented a number of entertaining theories. From a biological standpoint, some animal behaviorists suspect that a cat bolting after a deposit might stem from fears that a predator could track them based on the smell of their waste. But researchers are quick to note that they haven’t observed cats run from their BMs in the wild.

Biology also has a little bit to do with another theory, which postulates that cats used to getting their rear ends licked by their mother after defecating as kittens are showing off their independence by sprinting away, their butts having taken on self-cleaning properties in adulthood.

Not convinced? You might find another idea more plausible: Both humans and cats have a vagus nerve running from their brain stem. In both species, the nerve can be stimulated by defecation, leading to a pleasurable sensation and what some have labeled “poo-phoria,” or post-poop elation. In running, the cat may simply be working off excess energy brought on by stimulation of the nerve.

Less interesting is the notion that notoriously hygienic cats may simply want to shake off excess litter or fecal matter by running a 100-meter dash, or that a digestive problem has led to some discomfort they’re attempting to flee from. The fact is, so little research has been done in the field of pooping cat mania that there’s no universally accepted answer. Like so much of what makes cats tick, a definitive motivation will have to remain a mystery.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Animals
Listen to the Impossibly Adorable Sounds of a Baby Sloth
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RODRIGO ARANGUA/AFP/GettyImages

Sometimes baby sloths seem almost too adorable to be real. But the little muppet-faced treasures don't just look cute—turns out they sound cute, too. We know what you're thinking: How could you have gone your whole life without knowing what these precious creatures sound like? Well, fear not: Just in time for International Sloth Day (today), we have some footage of how the tiny mammals express themselves—and it's a lot of squeaking. (Or maybe that's you squealing?)

The sloths featured in the heart-obliterating video below come from the Sloth Sanctuary of Costa Rica. The institution rescues orphaned sloths, rehabilitates them, and gets them ready to be released back into the wild.

[h/t The Kid Should See This]

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