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.

Looking to Downsize? You Can Buy a 5-Room DIY Cabin on Amazon for Less Than $33,000

Five rooms of one's own.
Five rooms of one's own.
Allwood/Amazon

If you’ve already mastered DIY houses for birds and dogs, maybe it’s time you built one for yourself.

As Simplemost reports, there are a number of house kits that you can order on Amazon, and the Allwood Avalon Cabin Kit is one of the quaintest—and, at $32,990, most affordable—options. The 540-square-foot structure has enough space for a kitchen, a bathroom, a bedroom, and a sitting room—and there’s an additional 218-square-foot loft with the potential to be the coziest reading nook of all time.

You can opt for three larger rooms if you're willing to skip the kitchen and bathroom.Allwood/Amazon

The construction process might not be a great idea for someone who’s never picked up a hammer, but you don’t need an architectural degree to tackle it. Step-by-step instructions and all materials are included, so it’s a little like a high-level IKEA project. According to the Amazon listing, it takes two adults about a week to complete. Since the Nordic wood walls are reinforced with steel rods, the house can withstand winds up to 120 mph, and you can pay an extra $1000 to upgrade from double-glass windows and doors to triple-glass for added fortification.

Sadly, the cool ceiling lamp is not included.Allwood/Amazon

Though everything you need for the shell of the house comes in the kit, you will need to purchase whatever goes inside it: toilet, shower, sink, stove, insulation, and all other furnishings. You can also customize the blueprint to fit your own plans for the space; maybe, for example, you’re going to use the house as a small event venue, and you’d rather have two or three large, airy rooms and no kitchen or bedroom.

Intrigued? Find out more here.

[h/t Simplemost]

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Is It Illegal to Falsely Shout 'Fire' in a Crowded Theater?

Fortunately, nobody incited a stampede at New York's Metropolitan Opera House on this night in 1937.
Fortunately, nobody incited a stampede at New York's Metropolitan Opera House on this night in 1937.
National Archives and Records Administration, Wikimedia Commons // Public Domain

If you asked a few random people to name a situation that wouldn’t be protected under the First Amendment’s “freedom of speech” clause, there’s a pretty good chance at least one of them would mention the example of someone shouting “Fire!” in a crowded theater (when there’s no fire). Over the last century, the scene has been used far and wide to illustrate that if your “free speech” harms people, you can still end up in the defendant’s chair. But, as is so often the case when it comes to interpreting the law, it’s really not that simple.

Panic Room

The aftermath of the Iroquois Theatre fire.Fire-Truck.Ru, Wikimedia Commons // CC BY-SA 4.0

When people first started discussing human fire alarms at packed gatherings, it was less about constitutional debate and more about societal menace. During the late 18th and early 19th centuries, there were dozens of tragedies [PDF]—mainly in the U.S., but also abroad—where false shouts of “Fire!” provoked panic that resulted in multiple innocent, and avoidable, deaths. In 1913, for example, residents of Calumet, Michigan, held a Christmas party for the children of copper miners on strike. Hundreds of people gathered on the second floor of Italian Hall, and when an unidentified perpetrator (possibly motivated by anti-union sentiments) yelled “Fire!” they all rushed to the stairs. The stampede claimed 73 victims, most of whom were children.

The fear of fire wasn’t unfounded. Since not all buildings had sprinkler systems, neon exit signs, and capacity limits, plenty of fatal blazes occurred. More than 600 people died in Chicago’s Iroquois Theater fire in 1903, even though (ironically) that building was actually thought to be fireproof.

In short, shouting “Fire!” in a crowded theater was an idea firmly entrenched in the public consciousness by the time judges co-opted the phrase for legal arguments on First Amendment rights.

Discussing Fire in a Crowded Courtroom

We mustache Oliver Wendell Holmes Jr. a question about First Amendment rights.National Photo Company, Library of Congress Prints and Photographs Division, Wikimedia Commons // No Known Restrictions on Publication

The axiom became popular in legal spheres after Supreme Court Justice Oliver Wendell Holmes Jr. mentioned it during Schenck v. United States in 1919, but he wasn’t the first person to use it in court. As Carlton F.W. Lawson pointed out in a 2015 article in the William & Mary Bill of Rights Journal, U.S. attorney Edwin Wertz had uttered a lengthier version of it the previous year while prosecuting activist Eugene Debs. In fact, since Holmes ruled on Debs’s appeal the very week after the Schenck case, he may have even gotten the idea from Wertz.

Each case involved a violation of the Espionage Act of 1917, which essentially made it punishable to do anything that interfered with U.S. military operations—including speaking out against the draft. Debs, a pacifist who opposed World War I, was under fire for a speech he had given in Ohio; and Charles T. Schenck, the U.S. Socialist Party’s general secretary, landed in front of the Supreme Court for passing out pamphlets that encouraged men to refuse the draft.

Both defendants were convicted, and Holmes justified his ruling on the Schenck case with the explanation that “the most stringent protection of free speech would not protect a man in falsely shouting ‘fire’ in a theater and causing a panic.” But while his analogy struck an emotional chord, it really had nothing to do with constitutional law.

“The ‘crowded theater’ statement in Schenck never amounted to any kind of binding standard or doctrine,” Nashwa Gewaily, a media and First Amendment lawyer, tells Mental Floss. “It was basically a bit of emotionally charged extra flair from Justice Holmes, outside the official legal determination of that case; a powerful image that endured outside its context ... It was not a high point in American jurisprudence.”

“Revengeance” Is Fine

What Holmes said after it, however, did become a standard for future free speech arguments. “The question in every case,” he said, “is whether the words are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent.”

For the next 50 years, clear and present danger was the accepted—and slightly vague—metric for discerning if spoken or printed material was protected speech. Then, in 1969, the Supreme Court replaced it with something clearer. The case, Brandenburg v. Ohio, concerned a Ku Klux Klan leader named Clarence Brandenburg who had broken Ohio’s law against advocating “crime, sabotage, or unlawful methods of terrorism” for political purposes. (In his offending speech, he had mentioned the possibility of “revengeance” [sic] if the federal government didn’t stop “[suppressing] the white, Caucasian race.”)

Brandenburg appealed his guilty verdict all the way up to the Supreme Court, which overturned the ruling on the grounds that his threats were too ambiguous to “[incite] or [produce] imminent lawless action.” In order for something to qualify as imminent lawless action, it must: expressly advocate violence, advocate immediate violence, and relate to violence likely to occur.

As Gewaily explains, judges interpret this standard “far more narrowly than many would presume.” While individual institutions may condemn hate speech, for example, it’s technically protected under the law unless there’s “immediate violence” involved.

When Free Speech Is the Least of Your Worries

So, does falsely shouting “Fire!” in a crowded theater fall outside the conditions of imminent lawless action, and therefore fall under First Amendment protection? The short answer is that it depends on the circumstances. But here’s the long answer: If you get arrested for doing that, the charges brought against you might make the question of free speech totally irrelevant.

“The falsely shouted warning, while technically speech, could potentially violate a state's criminal laws against disturbing the peace or disorderly conduct, whether or not it provokes a stampede, for instance,” Gewaily says. And if there is a stampede in which somebody dies, you could be charged with involuntary manslaughter. In other words, there’s no law that explicitly prohibits you from crying “Fire” in a theater. It’s the other laws you’d have to worry about.

Shouting “Bomb!” or “Gun!” in public would put you in a similar situation. In May 2018, for example, officials had to evacuate part of Daytona Beach International Airport after a man ran naked through the building screaming about a bomb in the women’s bathroom. There was no bomb, but he was charged with “false report of a bomb,” “criminal mischief,” and “exposure of sexual organs,” among other things. In that case, no self-respecting lawyer would advise him to claim his actions were protected by the First Amendment.

That said, there’s good news for anyone whose panicked cry is an honest mistake. “Someone who shouts a warning in genuine error, with an intent to galvanize movement to safety, would not be properly punished for that speech,” Gewaily says.

And if Oliver Wendell Holmes Jr. has taught us anything, it’s that not every word a Supreme Court Justice says automatically counts as constitutional doctrine.

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