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Why Do Alligators Fall Asleep if You Rub Their Bellies?

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Myth has it that you can disarm an alligator by rubbing its belly. Some people don’t necessarily focus on the logistics of getting that close to the creature (let’s keep in mind the stomach is awfully close to all of those sharp teeth). However, we’re here to tell you that, yes, this is technically true—and alligators aren’t the only animals associated with this behavior.

"Belly rubbing refers to tonic immobility," the National's Zoo's Sean Henderson told The Washington Post in 2008. "It's a state of hypnotism generated by flipping the animal on its back and fully extending its neck" and, as we mentioned, stroking its belly. Fair warning, Henderson added: "Tonic immobility is generally brought about in an animal that is under heavily stressful conditions. Don't try this at home!"

According to Isaac Marks’s Fears, Phobias and Rituals: Panic, Anxiety, and Their Disorders, tonic immobility refers to the “prolonged stillness and decreased responsivity in a previously active animal in the face of threatening stimulation.” This state can last anywhere from 15 seconds to several hours, although the average length falls around eight to 10 minutes in chickens. (Yep, they can be affected too!)

Sharks are another type of creature susceptible to tonic immobility. There seem to be two different ways to trigger this effect in sharks, the most effective way being by rubbing a shark’s nose. While the exact reason why this works is unknown, one ecologist writes “[an] untested possibility is that a shark’s electroreceptors are concentrated in the snout area, and perhaps overstimulating this area ‘shocks’ them into immobility.”

Another means of immobilizing a shark is to invert it, flipping it on its back. WIRED recounted an especially odd occurrence of a shark being put into a state of tonic immobility—by another animal:

“In 1997, eyewitnesses watched a female orca off the coast of California seemingly induce tonic immobility purposely in a great white shark. The orca held the shark upside down, inducing tonic immobility, and kept the shark still for 15 minutes, which caused it to suffocate to death.”

Remember when we mentioned that tonic immobility occurs in chickens, too? WIRED theorizes that it’s a defense mechanism for the birds. “You can lay it on its side, tuck its head under its wing and gently rock it, or put it on its back and stroke its sternum,” the site reports. “You can wave your finger in front of its face—starting with your finger close to its beak and then pulling your finger slowly straight back. The chicken will focus on your finger.”

Tonic immobility affects different animals in different ways. "I've observed alpacas and llamas 'calmed' into a state of relaxation by gently rubbing the upper gum just beneath the cleft in the upper lip,” veterinary surgeon David Anderson told the Cincinnati Enquirer. “The animals stop resisting being held, and stop vocalizing.”

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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'Angry Badger' Terrorizes Scottish Castle, Forcing Closures 
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Portions of the 16th-century Craignethan Castle in Scotland were shut down last week after a less-than-friendly badger holed up there and refused to leave. Historic Environment Scotland, which manages the site in South Lanarkshire, sent out a tweet last Friday notifying visitors that the property's cellar tunnel would remain closed over the weekend “due to the presence of a very angry badger.” Staff tried to coax it out with cat food and honey, but the badger did what it wanted, and they were unable to move the mammal.

A spokesman for HES told the BBC, "The castle is surrounded by woodland and we believe the badger may have become lost. Staff first spotted some dug-out earth on Wednesday evening, and later spotted the badger on closer inspection."

On Saturday, staff used a GoPro camera to check out the tunnel from a safe distance and learned that the badger had left voluntarily, but not before making a mess. The critter dug through both soil and stonework, according to The Scotsman. The castle, an artillery fortification erected around 1530, is already partly in ruins.

Craignethan Castle in Scotland
Sandy Stevenson, Flickr // CC BY-NC-ND 2.0

Badgers are not typically dangerous, but they can become aggressive if they feel cornered or threatened. They can be seen year-round in Scotland, especially during spring and summer. Earthworms, bird eggs, small mammals, fruit, and roots are among their favorite meals, and they can even be “tempted into your garden by leaving peanuts out—a tasty snack for our striped friends,” the Scottish Wildlife Trust says.

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Why Do Cats Sleep So Much?
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Cats can sleep 16 to 20 hours a day. It’s not always deep sleep. Cats spend a lot of time taking short “cat naps” that build their energy, yet keep them alert enough to jump up the moment they sense danger or excitement. They don't sleep a lot because they’re lazy or bored. Cats sleep so that they’re ready to hunt.

Their genes (geenz) tell them to. Genes are the tiny instructions inside the cells of all living things that make a species look and act certain ways. These instructions get passed down from parents to kids. In the case of cats, their genes tell them to sleep a lot, especially during the day. 

A long time ago, cats weren’t domesticated (Doh-MESS-tih-cay-ted). That means they were wild and didn't live with humans. Cats had to hunt to survive, and they needed a lot of energy for that. Just like lions, tigers, and other wild cats, domesticated cats sleep more during the day so they’ll be ready to hunt at night, especially around sunrise and sunset. Of course, most house cats no longer have to hunt at all. But just in case they do, their genes tell them to nap often so they’ll be ready.

Cats can sleep in some pretty strange places, as you can see in this video

 

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