Why Do Bats Hang Upside Down?

iStock.com/CraigRJD
iStock.com/CraigRJD

Stefan Pociask:

The age-old question of upside down bats. Yes, it is awfully weird that there is an animal—a mammal even—that hangs upside down. Sure, some monkeys do it when they're just monkeying around. And a few other tree climbers, like margays, hang upside down if they are reaching for something or—again, like the margay cat—may actually even hunt that way ... But bats are the only animals that actually spend most of their time hanging upside down: feeding this way, raising their young this way, and, yes, sleeping or roosting this way.

There is actually a very good and sensible reason why they do this: They have to hang upside down so that they can fly.

First off, we have to acknowledge that bats are not birds, nor are they insects. These are the other two animals that have true powered flight (as opposed to gliding). The difference between bat flight and bird or insect flight is weight—specifically, the ratio of weight to lift-capacity of the wings. If you walk up to a bird or insect, most species will be able to fly right up into the air from a motionless position, and do it quickly.

Bats, on the other hand (or, other wing), can’t do that. They have a lot of difficulty taking off from the ground (not that they can’t do it ... it’s just more difficult). Insects and birds often actually jump into the air to give them a start in the right direction, then their powerful wings take them up, up, and away.

Birds have hollow bones; bats don’t. Insects are made of lightweight chitin or soft, light tissue; bats aren’t. And bats don’t have what you could call "powerful" wings. These amazing creatures are mammals, after all. The only flying mammals. Nature found a way to evolve such an unlikely thing as a flying mammal, so some compromises had to be made. Bats, once airborne, manage perfectly well in the air, and can literally fly circles around most birds in flight. The problem is in first getting off the ground.

To compensate for the extra weight that mammals must have, to compensate for the problem of getting off the ground, evolution found another way for bats to transition from being motionless to immediately being able to fly when necessary. Evolution said, “How about if we drop them from above? That way they are immediately in the air, and all they need to do is start flapping."

It was a great idea, as it turns out. Except bat feet aren’t any good for perching on a branch. They are mammals, not birds, so their musculature, their bones, and their tendons are set up in a completely different way. When a bird squats down on a branch, their tendons actually lock their toes into an even tighter grip on the perch. It happens automatically. That’s part of being a bird, and is universal. That’s why they don’t fall off in their sleep.

Bats, as mammals, are set up differently. Therefore, to compensate for that fact, nature said, “How about if we have them hang upside down? That way, their tendons will actually pull their toes closed, just like a bird does from the opposite direction.” So that’s what evolved. Bats hang from the bottom of something, and all they have to do is "let go" and they are instantly flying. In fact, with this gravity-assist method, they can achieve instant flight even faster than birds, who have to work against gravity.

Side note: In case you were wondering how bats poop and pee while upside down ... First off, pooping is no big deal. Bat poop looks like tiny grains of rice; if they are hanging, it just falls to the floor of the bat cave as guano. Pee, however ... well, they have that covered too. They just “hold it” until they are flying.

So there you go. Bats sleep hanging upside down because they are mammals and can’t take off into the air like birds can (at least not without difficulty). But, if they're hanging, all they do is let go.

Makes total sense, right?

Now, having said all that about upside down bats, I must mention the following: Not all of the 1240-plus species of bats do hang upside down. There are exceptions—about six of them, within two different families. One is in South America (Thyropteridae) and the other is in Madagascar (Myzopodidae). The Myzopodidae, which includes just one species, is exceedingly rare.

So it turns out that these bats roost inside the tubes of young, unfurled banana leaves and other similar large leaves. When they attach themselves to the inside of this rolled leaf, they do it head-up. The problem with living inside of rolled-up leaves is that within a few days, these leaves will continue growing, and eventually open up. Whenever that happens, the whole group of bats has to pick up and move to another home. Over and over again. All six of these species of rare bats have a suction cup on each wrist and ankle, and they use these to attach to the smooth surface of the inside of the leaf tube. Evolution: the more you learn, the more amazing it becomes.

This post originally appeared on Quora. Click here to view.

Amazon’s Big Fall Sale Features Deals on Electronics, Kitchen Appliances, and Home Décor

Dash/Keurig
Dash/Keurig

If you're looking for deals on items like Keurigs, BISSELL vacuums, and essential oil diffusers, it's usually pretty slim pickings until the holiday sales roll around. Thankfully, Amazon is starting these deals a little earlier with their Big Fall Sale, where customers can get up to 20 percent off everything from home decor to WFH essentials and kitchen gadgets. Now you won’t have to wait until Black Friday for the deal you need. Make sure to see all the deals that the sale has to offer here and check out our favorites below.

Electronics

Dash/Amazon

- BISSELL Lightweight Upright Vacuum Cleaner $170 (save $60)

- Dash Deluxe Air Fryer $80 (save $20)

- Dash Rapid 6-Egg Cooker $17 (save $3)

- Keurig K-Café Single Coffee Maker $169 (save $30)

- COMFEE Toaster Oven $29 (save $9)

- AmazonBasics 1500W Oscillating Ceramic Heater $31 (save $4)

Home office Essentials

HP/Amazon

- HP Neverstop Laser Printer $250 (save $30)

- HP ScanJet Pro 2500 f1 Flatbed OCR Scanner $274 (save $25)

- HP Printer Paper (500 Sheets) $5 (save $2)

- Mead Composition Books Pack of 5 Ruled Notebooks $11 (save $2)

- Swingline Desktop Hole Punch $7 (save $17)

- Officemate OIC Achieva Side Load Letter Tray $15 (save $7)

- PILOT G2 Premium Rolling Ball Gel Pens 12-Pack $10 (save $3)

Toys and games

Selieve/Amazon

- Selieve Toys Old Children's Walkie Talkies $17 (save $7)

- Yard Games Giant Tumbling Timbers $59 (save $21)

- Duckura Jump Rocket Launchers $11 (save $17)

- EXERCISE N PLAY Automatic Launcher Baseball Bat $14 (save $29)

- Holy Stone HS165 GPS Drones with 2K HD Camera $95 (save $40)

Home Improvement

DEWALT/Amazon

- DEWALT 20V MAX LED Hand Held Work Light $54 (save $65)

- Duck EZ Packing Tape with Dispenser, 6 Rolls $11 (save $6)

- Bissell MultiClean Wet/Dry Garage Auto Vacuum $111 (save $39)

- Full Circle Sinksational Sink Strainer with Stopper $5 (save $2)

Home Décor

NECA/Amazon

- A Christmas Story 20-Inch Leg Lamp Prop Replica by NECA $41 save $5

- SYLVANIA 100 LED Warm White Mini Lights $8 (save 2)

- Yankee Candle Large Jar Candle Vanilla Cupcake $17 (save $12)

- Malden 8-Opening Matted Collage Picture Frame $20 (save $8)

- Lush Decor Blue and Gray Flower Curtains Pair $57 (save $55)

- LEVOIT Essential Oil Diffuser $25 (save $5)

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Why Do Dogs Like to Bury Things?

Dogs like to dig.
Dogs like to dig.
Nickos/iStock via Getty Images

If you’ve ever found your dog’s favorite toy nestled between pillows or under a pile of loose dirt in the backyard, then you’ve probably come to understand that dogs like to bury things. Like many of their behaviors, digging is an instinct. But where does that impulse come from?

Cesar's Way explains that before dogs were domesticated and enjoyed bags of processed dog food set out in a bowl by their helpful human friends, they were responsible for feeding themselves. If they caught a meal, it was important to keep other dogs from running off with it. To help protect their food supply, it was necessary to bury it. Obscuring it under dirt helped keep other dogs off the scent.

This behavior persists even when a dog knows some kibble is on the menu. It may also manifest itself when a dog has more on its plate than it can enjoy at any one time. The ground is a good place to keep something for later.

But food isn’t the only reason a dog will start digging. If they’ve nabbed something of yours, like a television remote, they may be expressing a desire to play.

Some dog breeds are more prone to digging than others. Terriers, dachshunds, beagles, basset hounds, and miniature schnauzers go burrowing more often than others, though pretty much any dog will exhibit the behavior at times. While there’s nothing inherently harmful about it, you should always be sure a dog in your backyard isn’t being exposed to any lawn care products or other chemicals that could prove harmful. You should also probably keep your remote in a safe place, before the dog decides to relocate it for you.

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