15 Amazing Sleeping Habits of Animals

iStock
iStock

Animals don't have sleeping masks or soothing prerecorded sounds to help them get the sleep they need, so they have to make do with what nature and their bodies allow. Consequently, many have found some incredible ways to get their much-needed rest.

1. DOLPHINS

Bottlenose dolphins underwater
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Dolphins are amazing creatures, and while they are usually noted for their adorableness, wits and/or disturbing sexual aggression, their sleeping habits are worth mentioning too. They can enter into periods of very deep sleep referred to as "logging" because while in it, a dolphin looks like a log floating at the surface of the water. Crazier still, the bottlenose dolphin readies itself for slumber by literally shutting down half of its brain, as well as the eye opposite the powered-down hemisphere. The other half of the brain (and opposite eye) stays turned on to watch out for whatever might come along, whether be it other dolphins or predators. It also tells the dolphin when to come up for air. After two hours or so, the sides switch, so both eyes and brain hemispheres get their due rest. This process isn't unique to dolphins, as fruit bats, porpoises, iguanas, seals, birds, and ducks do it too.

2. SPERM WHALES

A sperm whale floats near the surface of the water.
iStock

In 2008, researchers happened upon a group of sleeping sperm whales bobbing vertically in the water off the coast of northern Chile. The sight alone was amazing, but then things got strange. These whales, which were thought to only allow one side of their brain to rest at a time, like dolphins and some other whales, didn't seem to notice the approaching vessel. It wasn't until one of the cetaceans was accidentally nudged that the group woke up and fled. Through this discovery, researchers learned that sperm whales sleep differently from their relatives—in short, regular periods of full sleep near the surface. They don't breathe or move during their naps, and if this is the only kind of sleep they get (it's unclear whether they also engage in half-brain sleep), the relatively short amount of cumulative slumber might make them the least sleep-dependent of all mammals.

3. GIRAFFES

Baby giraffe sleeping on the ground
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Giraffes don't rest much longer than sperm whales do. They sleep about 20 minutes a day in order to avoid predators. Being such a tall, lanky beast also makes it difficult to catch some quick z's, but when they do curl up for some rest, it's pretty adorable.

4. SEA OTTERS

Two sleeping otters holding hands in the water.
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Predators aren't the only issue to navigate while asleep. As otters know, there's also the possibility of drifting off (pun absolutely intended). When sea otters fall asleep, they do so while lying on their backs at the surface of the water and in groups or in seaweed forests, sometimes holding hands to keep from floating apart.

5. ALBATROSSES

An albatross flying over the waves.
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The albatross is a sea bird that spends much of its life soaring around on the hunt. Its lifestyle doesn't leave a lot of time for snoozing, so it's believed the albatross multitasks by sleeping while flying. Alpine swifts are believed to do this too, as are migratory Swainson's Thrush birds, who take hundreds of little power naps lasting only a few seconds each.

6. DUCKS

Ducks standing in a row.
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Our feathered friends do more than sleep with one eye open. They sleep in a clique. Ducks queue up in a row when it's time to hit the hay, and the ones at the end of the line keep the eye facing away from the group open to watch out for predators, and close the other eye. The ducks inside close both of their eyes. The single-hemisphere sleep in the bookending ducks keeps the whole row safe.

7. MEERKATS

A pile of sleeping meerkats.
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Meerkats spend their nights in burrows, which consist of complex tunnel systems and underground sleeping quarters. Communities of meerkats are called mobs or gangs and can consist of up to 40 animals with an alpha male and female in each community. They sleep in heaps, getting warmth from one another and protecting the gang leaders at the bottom of the pile. Puppies, squirrels, bats, and a slew of other creatures are also known to huddle up for warmth during sleep (including the elusive homo sapiens).

8. HORSES, ZEBRAS, AND ELEPHANTS

A zebra mother and her foal standing in the desert.
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This is the crew of the standing sleepers, who stay alert during their rest by remaining on their feet. These animals are able to lock their legs in a straight standing position in such a way that it doesn't require much muscle effort. This is called a "stay apparatus." While it's a cool trick, horses (and cows too) do need to lie down from time to time, because they can't achieve REM sleep while standing up. Flamingos sleep while standing too, but they do so because there aren't many cozy places to slumber in their usual habitats.

9. BROWN BATS

Bats hanging from a cave ceiling and sleeping.
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On the other side of the mammalian sleep spectrum from sperm whales and giraffes are brown bats, which sleep about 19 hours a day. The nocturnal creatures snooze upside down all day, a stance born of efficiency, as it's easier for them and their weak wings to take off from that position. After bats, the lengthiest daily sleepers are armadillos, opossums, sloths, tigers, and then domestic cats. Keep that in mind next time you want to tell your feline to get a job.

10. SHARKS

A shark with smaller fish getting out of its way.
iStock

Most sharks have to keep moving constantly in order to get oxygen through their gills, while others have developed spiracles, openings behind the eye that allow them to take in oxygen while stationary. But generally their sleep is thought to be more of an idle state than a full-fledged shut down. Scientists have found that the spiny dogfish's swimming might be coordinated by the spinal cord and not the brain, which would indicate that sharks might be able to power down their noggins and continue moving after all. Others speculate that some white sharks might face the current while stationary, so water moves over their gills with no effort from the fish itself.

11. WALRUSES

Hundreds of walruses sleeping together.
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Walruses can also sleep and swim at the same time. They're also basically that friend of yours who can fall asleep anywhere—they can hold their breath for up to five minutes and catch a nap underwater, or deep-sleep ashore for as many as 19 hours. They deserve a deep slumber though—walruses have been known to swim continuously for up to 84 hours. For water sleeping, walruses can inflate spaces in their bodies called pharyngeal pouches, which act as sort of a biological life jacket to keep the blubbery beasts afloat.

12. DESERT SNAIL

Desert snail on the ground.
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It doesn't seem like a snail would have a very taxing life, but these little slimy creatures can go on sleeping for literally years. One particularly famous incident involved an Egyptian desert snail who was assumed dead by a British Museum staffer who affixed the snail to an identification card. Four years later, traces of slime were discovered on the card, and when the staff removed the shell from the card, the animal crawled out.

13. FROGS

Freezing frog in hibernation.
iStock

Frogs survive winter by hibernating much like their larger, furrier friends, but their feats are arguably way more incredible. Frogs are equipped with a kind of animal antifreeze, which means that while ice crystals may form in body cavities and under the skin, high concentrations of glucose in its vital organs prevents those essential parts from freezing. A partially frozen frog stops breathing and its heart ceases beating, but when the spring thaw comes and temperatures start to rise, its body resumes its functions and springs back to life.

14. BEARS

Mother bear and two cubs in the woods.
iStock

The sleeping habits of bears aren't usually anything notable, except when it's time to give birth. In the winter months, when pregnant mothers are deep in hibernation mode, their heart rates slow, and they stop eating, drinking, urinating, defecating, or exercising. But mama bears will rouse themselves enough to do a little thing called giving birth. The cubs then nurse on their sleeping mom for the next few months until she wakes up and takes them out into the world.

15. APES

Orangutan sleeping on a tree limb.
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Scientists are studying apes to learn things about the way humans sleep and how that might have helped us evolve. They've found that animals like the orangutan, gorilla, and chimpanzee all like to curl up to sleep just like humans. They also make beds or find platforms for predator-free slumber, which consequently helps them sleep better than counterparts such as the upright-sleeping baboon. That chance for a longer, more restful sleep might have been a factor in our own evolutionary process, helping us to get smarter with each 40 winks.

This story originally ran in 2015.

Amazon's Best Black Friday Deals: Tech, Video Games, Kitchen Appliances, Clothing, and More

Amazon
Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

Black Friday is finally here, and Amazon is offering great deals on kitchen appliances, tech, video games, and plenty more. We will keep updating this page as sales come in, but for now, here are the best Amazon Black Friday sales to check out.

Kitchen

Instant Pot/Amazon

- Instant Pot Duo Plus 9-in-115 Quart Electric Pressure Cooker; $90 (save $40)

- Keurig K-Cafe Special Edition; $190 (save $30)

- Ninja OS301 Foodi 10-in-1 Pressure Cooker and Air Fryer; $125 (save $75)

- Nespresso Vertuo Next Coffee and Espresso Machine by Breville; $120 (save $60)

- KitchenAid KSMSFTA Sifter with Scale Attachment; $95 (save $75)

- Keurig K-Mini Coffee Maker; $60 (save $20)

- Cuisinart Bread Maker; $80 (save $97)

- Anova Culinary Sous Vide Precision Cooker; $139 (save $60)

- Aicook Juicer Machine; $35 (save $15)

- JoyJolt Double Wall Insulated Espresso Mugs - Set of Two; $14 (save $10)

- Longzon Silicone Stretch Lids - Set of 14; $16 (save $11)

- HadinEEon Milk Frother; $37 (save $33)

Home Appliances

Roomba/Amazon

- iRobot Roomba 675 Robot Vacuum with Wi-Fi Connectivity; $179 (save $101)

- ASAKUKI 500ml Premium Essential Oil Diffuser; $22 (save $4)

- Facebook Portal Smart Video Calling 10 inch Touch Screen Display with Alexa; $129 (save $50)

- Bissell air320 Smart Air Purifier with HEPA and Carbon Filters; $280 (save $50)

- Oscillating Quiet Cooling Fan Tower; $59 (save $31)

- TaoTronics PTC 1500W Fast Quiet Heating Ceramic Tower; $55 (save $10)

- Vitamix 068051 FoodCycler 2 Liter Capacity; $300 (save $100)

- Ring Video Doorbell; $70 (save $30)

Video games

Sony

- Marvel's Spider-Man: Game of The Year Edition for PlayStation 4; $20 (save $20)

- The Legend of Zelda: Link's Awakening; $40 (save $20)

- Hyrule Warriors: Age of Calamity; $50 (save $10)

- Marvel's Avengers; $25 (save $33)

- The Last of Us Part II for PlayStation 4; $30 (save $30)

- LEGO Harry Potter: Collection; $15 (save $15)

- Ghost of Tsushima; $40 (save $20)

- BioShock: The Collection; $20 (save $30)

- The Sims 4; $24 (save $20)

- God of Warfor PlayStation 4; $10 (save $10)

- Days Gonefor PlayStation 4; $20 (save $6)

- Luigi's Mansion 3 for Nintendo Switch; $40 (save $20)

Computers and tablets

Microsoft/Amazon

- New Apple MacBook Pro 16 inches with 512 GB; $2149 (save $250)

- Microsoft Surface Laptop 3 with 13.5 inch Touch-Screen; $1200 (save $400)

- Lenovo ThinkPad T490 Laptop; $889 (save $111)

- Amazon Fire HD 10 Tablet (64GB); $120 (save $70)

- Amazon Fire HD 10 Kids Edition Tablet (32 GB); $130 (save $70)

- Apple iPad Mini (64 GB); $335 (save $64)

- Vankyo MatrixPad S2 Tablet; $120 (save $10)

Tech, gadgets, and TVs

Apple/Amazon

- Apple Watch Series 3 with GPS; $120 (save $79)

- Seneo Wireless Charger, 3 in 1 Wireless Charging Station; $16 (save $10)

- SAMSUNG 75-inch Class Crystal 4K Smart TV; $998 (save $200)

- Nixplay 2K Smart Digital Picture Frame 9.7 Inch Silver; $238 (save $92)

- All-New Amazon Echo Dot with Clock and Alexa (4th Gen); $39 (save $21)

- MACTREM LED Ring Light 6" with Tripod Stand; $16 (save $3)

- Amazon Fire TV Stick with Alexa Voice Remote; $28 (save $12)

- DR. J Professional HI-04 Mini Projector; $93 (save $37)

Headphones and speakers

Beats/Amazon

- Beats Solo3 Wireless On-Ear Headphones; $120 (Save $80)

- Apple AirPods Pro; $169 (save $50)

- Anker Soundcore Upgraded Bluetooth Speaker; $22 (save $8)

- Powerbeats Pro Wireless Earphones; $175 (save $75)

- JBL Boombox; $280 (save $120)

Movies and TV

HBO/Amazon

- Game of Thrones: The Complete Series; $115 (save $89)

- Jurassic World 5-Movie Set; $23 (save $37)

- Deadwood: The Complete Series; $42 (save $28)

- Back to the Future Trilogy; $15 (save $21)

Toys and Games

Amazon

- Awkward Family Photos Greatest Hits; $15 (save $10)

- Exploding Kittens Card Game; $10 (save $10)

- Cards Against Humanity: Hidden Gems Bundle; $14 (save $5)

- LOL Surprise OMG Remix Pop B.B. Fashion Doll; $29 (save $6)

- LEGO Ideas Ship in a Bottle 92177 Expert Building Kit; $56 (save $14)

Furniture

Casper/Amazon

- Casper Sleep Element Queen Mattress; $476 (save $119)

- ZINUS Alexis Deluxe Wood Platform Bed Frame; $135 (save $24)

- ROMOON Dresser Organizer with 5 Drawers; $59 (save $11) 

- AmazonBasics Room Darkening Blackout Window Curtains; $26 (save $5)

- Writing Desk by Caffoz; $119 (save $21)

- SPACE Seating Office Support Managers Chair; $112 (save $116)

- Rivet Globe Stick Table Lamp; $53 (save $17)

- Christopher Knight Home Merel Mid-Century Modern Club Chair; $188 (save $10)

- Walker Edison Furniture Industrial Rectangular Coffee Table; $121 (save $48)

Beauty

Haus/Amazon

- MySmile Teeth Whitening Kit with LED Light; $21 (save $12) 

- Cliganic USDA Organic Lip Balms Set of Six; $6 (save $4)

- HAUS LABORATORIES By Lady Gaga: LE RIOT LIP GLOSS; $7 (save $11)

- Native Deodorant for Men and Women Set of Three; $25 (save $11) 

- BAIMEI Rose Quartz Jade Roller & Gua Sha; $14 (save $3)

- Honest Beauty Clearing Night Serum with Pure Retinol and Salicylic Acid; $20 (save $8)

- WOW Apple Cider Vinegar Shampoo and Hair Conditioner Set; $30 (save $5) 

- La Roche-Posay Effaclar Purifying Foaming Gel Cleanser; $15 (save $5)

- wet n wild Bretman Rock Shadow Palette; $9 (save $6)

- EltaMD UV Daily Tinted Face Sunscreen Moisturizer with Hyaluronic Acid; $25 (save $6)

Clothes

Ganni/Amazon

- Ganni Women's Crispy Jacquard Dress; $200 (save $86) 

- The Drop Women's Maya Silky Slip Skirt; $36 (save $9)

- Steve Madden Women's Editor Boot; $80 (save $30)

- adidas Women's Roguera Cross Trainer; $40 (save $25)

- Line & Dot Women's Elizabeth Sweater; $74 (save $18)

- Levi's Men's Sherpa Trucker Jacket; $57 (save $41)

- Adidas Men's Essentials 3-Stripes Tapered Training Joggers Sweatpants; $28 (save $12)

- Timex Men's Weekender XL 43mm Watch; $32 (save $20)

- Ray-Ban Unisex-Adult Hexagonal Flat Lenses Sunglasses; $108 (save $46) 

- Reebok Men's Flashfilm Train Cross Trainer; $64 (save $16)

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Watch: In 1948, Idaho Officials Sent 76 Beavers Parachuting Into Idaho’s Wilderness

A young beaver with all four feet firmly on the ground.
A young beaver with all four feet firmly on the ground.
yrjö jyske, Flickr // CC BY 2.0

When people started building up the area around Idaho’s Payette Lake after World War II, its original residents began interfering with irrigation and agricultural endeavors. They weren’t exactly staging an organized protest—they were just beavers doing what beavers do.

Nevertheless, officials at the Idaho Department of Fish and Game decided their best bet was to find a new home for the long-toothed locals. The surrounding wilderness provided plenty of options, but transportation was another issue entirely. Traversing the undeveloped, mountainous terrain would require both trucks and pack animals, and experts knew from past relocation efforts that beavers weren’t fond of either.

“Beavers cannot stand the direct heat of the sun unless they are in water,” department employee Elmo W. Heter explained in a 1950 report [PDF]. “Sometimes they refuse to eat. Older individuals often become dangerously belligerent ... Horses and mules become spooky and quarrelsome when loaded with a struggling, malodorous pair of live beavers.”

To keep Payette Lake’s beavers healthy and happy during the journey, their human handlers would need to find another method of travel. As Boise State Public Radio reports, that’s when Heter suggested making use of their leftover WWII parachutes.

Two beavers would sit inside a wooden box attached to a parachute, which could be dropped from an airplane between 500 and 800 feet above their new home in the Chamberlain Basin. The cables that fastened the box to the parachute would keep it shut during the flight, but they’d slacken enough for the beavers to open the box upon landing. After testing the operation with weights, Heter and his colleagues enlisted an older beaver named Geronimo for a few live trials.

“Poor fellow!” Heter wrote. “You may be sure that ‘Geronimo’ had a priority reservation on the first ship into the hinterland, and that three young females went with him.”

Once Geronimo had certified the safety of the mission, the team began migrating the whole beaver population. During the fall of 1948, a total of 76 beavers touched down in their new territory. It wasn’t without tragedy, though; one beaver fell to his death after a cable broke on his box. Overall, however, the venture was deemed much safer (and less expensive) than any trip on foot would have been. And when department officials checked in on the beavers a year later, they had already started improving their ecosystem.

“Beavers had built dams, constructed houses, stored up food, and were well on their way to producing colonies,” Heter wrote. As Idaho Fish and Game’s Steve Liebenthal told Boise State Public Radio, the area is now part of “the largest protected roadless forest” in the continental U.S.

You can watch the Idaho Fish and Game Commission’s full 14-minute documentary about the process below.

[h/t Boise State Public Radio]