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Octopuses Change Colors to Intimidate Their Foes, Study Finds

Octopuses are well-known for being anti-social, but new research is proving they aren’t as reclusive as scientists previously believed. In fact, their knack for changing their appearance—long thought of as an effective way to hide—may also be a way they communicate with other octopuses, a new study finds. Research from Alaska Pacific University and the University of Sydney published in Current Biology indicates that the ability to change the hue of their bodies plays an important role in conflicts between octopuses.

The researchers studied a species called Octopus tetricus by setting up cameras in the shallow waters of Jervis Bay off the eastern coast of Australia. In more than 50 hours of video, they catalogued 186 octopus interactions, noticing a pattern in the social lives of the eight-tentacled creatures: They tend to turn dark colors when they feel aggressive.

The octopus in the background of the photo is adopting an aggressive posture, while the pale octopus in the foreground is being submissive.

When a dark-colored octopus approached another dark-colored octopus, the two were more likely to fight, whereas if a light-colored octopus met a dark octopus, the paler of the two was likely to scuttle off in retreat. Dark octopuses were more likely to stand their ground during a beef, while lighter octopuses were more likely to beat it.

In addition to dimming the color of their bodies, aggressive octopuses typically stand up tall and spread their web out in a position "nicknamed the Nosferatu pose,” making themselves look as large and forbidding as possible, while submissive octopuses will slink down.

This adds to previous research that found that octopuses can be social in captivity, even cohabitating in dens. The authors of the current study suggest that octopuses may behave more socially in areas where there’s a lot of food to be had, but limited places to hide. The growing body of evidence for octopus interactions (that don’t involve eating each other) “indicates that we should no longer consider octopuses as solitary and asocial,” they write.

[h/t: NPR]

All images by David Scheel

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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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Big Questions
Why Do Cats Sleep So Much?
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Chloe Effron / iStock

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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