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All Mammals Take the Same Amount of Time to Poop, Scientists Find

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Yes, everyone poops. Moreover, at least when it comes to mammals, everyone poops for about the same amount of time, according to a new study. The research, described in the journal Soft Matter and brought to our attention by the Science of Us, examined mammals as small as cats and as large as elephants, finding that they all took around 12 seconds to defecate.

The study examined elephants, giant pandas, and warthogs at the Zoo Atlanta, dogs at a park, the dimensions of feces and large intestines, and mathematical models to better understand how animals poop. The Georgia Institute of Technology researchers found that regardless of the animal’s total size, the mammals studied had feces that were double the length of their rectum, and whether that rectum was an inch-and-a-half long or almost 16 inches long, their feces took about 12 seconds to exit the body.

The researchers only studied animals with cylindrical feces (excluding rabbits, rodents, and ruminants like cows in the process), collecting stool samples from 34 zoo animals, seven farm animals, and two species of animals (unidentified) living at Georgia Tech. They also observed animals pooping at Zoo Atlanta firsthand and watched 19 different YouTube videos that featured animals doing their business.

Through their observations and theoretical calculations on the fluid mechanics of defecation, the researchers found that all animals exert the same amount of pressure while pooping. They also found that bigger animals had more poop to get rid of, but they also had thicker mucus layers lining the walls of their large intestine, which helps move the poop out of the body at a faster clip. Combine these two factors, and you get pretty consistent poop durations across the animal kingdom—12 seconds—despite the wide range of body sizes. (Constipation happens when the feces moving through the large intestine soak up that mucus layer. Think of it like trying to go down a waterslide that is completely dry.)

This study did not examine every animal on Earth, but the finding is in line with research on the other potty habits of mammals. Previous work—awarded an Ig Nobel Prize in 2015—found that all mammals pee for about the same amount of time (21 seconds). It’s evolutionarily plausible, too. Pooping makes it hard to run away from predators (a significant number of sloths die when they leave the treetops to poop at ground level, in fact) and a quick heave-ho of the bowels is safer than straining in one location for 20 minutes.

The researchers hope their study will be used for more than just satisfying the curiosity of colon obsessives, though. “By understanding the physics of defecation, we will provide not only new ideas for medical diagnostics, diapers, and incontinence products but also transport methods for the feces of humans, pets, and agriculturally important animals,” they write.

[h/t Science of Us]

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What Pop Culture Gets Wrong About Dissociative Identity Disorder
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From the characters in Fight Club to Dr. Jekyll and Mr. Hyde, popular culture is filled with "split" personalities. These dramatic figures might be entertaining, but they're rarely (if ever) scientifically accurate, SciShow Psych's Hank Green explains in the channel's latest video. Most representations contribute to a collective misunderstanding of dissociative identity disorder, or DID, which was once known as multiple personality disorder.

Experts often disagree about DID's diagnostic criteria, what causes it, and in some cases, whether it exists at all. Many, however, agree that people with DID don't have multiple figures living inside their heads, all clamoring to take over their body at a moment's notice. Those with DID do have fragmented personalities, which can cause lapses of memory, psychological distress, and impaired daily function, among other side effects.

Learn more about DID (and what the media gets wrong about mental illness) by watching the video below.

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Scientists Reveal Long-Hidden Text in Alexander Hamilton Letter
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Age, deterioration, and water damage are just a few of the reasons historians can be short on information that was once readily available on paper. Sometimes, it’s simply a case of missing pages. Other times, researchers can see “lost” text right under their noses.

One example: a letter written by Alexander Hamilton to his future wife, Elizabeth Schuyler, on September 6, 1780. On the surface, it looked very much like a rant about a Revolutionary War skirmish in Camden, South Carolina. But Hamilton scholars were excited by the 14 lines of writing in the first paragraph that had been crossed out. If they could be read, they might reveal some new dimension to one of the better-known Founding Fathers.

Using the practice of multispectral imaging—sometimes called hyperspectral imaging—conservationists at the Library of Congress were recently able to shine a new light on what someone had attempted to scrub out. In multispectral imaging, different wavelengths of light are “bounced” off the paper to reveal (or hide) different ink pigments. By examining a document through these different wavelengths, investigators can tune in to faded or obscured handwriting and make it visible to the naked eye.

A hyperspectral image of Alexander Hamilton's handwriting
Hyperspectral imaging of Hamilton's handwriting, from being obscured (top) to isolated and revealed (bottom).
Library of Congress

The text revealed a more emotional and romantic side to Hamilton, who had used the lines to woo Elizabeth. Technicians uncovered most of what he had written, with words in brackets still obscured and inferred:

Do you know my sensations when I see the
sweet characters from your hand? Yes you do,
by comparing [them] with your [own]
for my Betsey [loves] me and is [acquainted]
with all the joys of fondness. [Would] you
[exchange] them my dear for any other worthy
blessings? Is there any thing you would put
in competition[,] with one glowing [kiss] of
[unreadable], anticipate the delights we [unreadable]
in the unrestrained intercourses of wedded love,
and bet your heart joins mine in [fervent]
[wishes] to heaven that [all obstacles] and [interruptions]
May [be] speedily [removed].

Hamilton and Elizabeth Schuyler married on December 14, 1780. So why did Hamilton try and hide such romantic words during or after their courtship? He probably didn’t. Historians believe that his son, John Church Hamilton, crossed them out before publishing the letter as a part of a book of his father’s correspondence. He may have considered the passage a little too sexy for mass consumption.

[h/t Library of Congress]

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