Nature

WTF Fun Fact 13188 – Geckos Turn Off Sticky Feet

People have long wondered how geckos manage to stick to the sides of structures without falling off. The short answer is that they have sticky feet. But did you know geckos turn off sticky feet when they need to run faster?

How do geckos turn off sticky feet?

Geckos use toe hairs to turn the stickiness of their feet on and off. Oregon State University (OSU) discovered the details of this mechanism in 2014. They published their results in an article that appears in the Journal of Applied Physics.

The researchers noted that the geckos’ “adhesion system mechanism” has long been a curiosity. According to Science Daily (cited below):

“‘Since the time of the ancient Greeks, people have wondered how geckos are able to stick to walls — even Archimedes is known to have pondered this problem,’ said Alex Greaney, co-author and an assistant professor of engineering at OSU. ‘It was only very recently, in 2000, that Kellar Autumn and colleagues proved unequivocally that geckos stick using van der Waals forces.'”

Geckos have a system of hairs called “seta” on their toes. The seta can bend when they come into contact with rough surfaces in order to provide points of contact that keep the sticky surface of the gecko’s toe pads from adhering. Those hairs provide millions of points of contact to allow the creatures to maneuver over terrain without sticking.

Other insects and spiders also have this adhesion system. That’s why they can stick sideways to walls, seeming to defy gravity.

The stickiness system

Greany told Science Direct: “Understanding the subtleties of the process for switching stickiness on and off is groundbreaking. By using mathematical modeling, we’ve found a simple, but ingenious, mechanism allows the gecko to switch back and forth between being sticky or not. Geckos’ feet are by default nonsticky, and this stickiness is activated through application of a small shear force. Gecko adhesion can be thought of as the opposite of friction.”

The stickiness of geckos’ feet has long fascinated scientists seeking to produce material for use in adhesives. The ability of geckos to turn off sticky feet is yet another piece of the materials science puzzle that may come in handy someday in fields like construction and robotics. — WTF fun facts

Source: “Geckos use toe hairs to turn stickiness on and off” — ScienceDaily

WTF Fun Fact 13182 – Peppa Pig Episode Banned in Australia

If you’re not a parent of a little one, there’s a good chance you’re not familiar with Peppa Pig. The animated show is British, aimed at preschool-aged children. It follows the adventures of a female pig and her family. Riveting stuff. But it actually does get interesting if you know that there was a Peppa Pig episode banned in Australia!

Why was a Peppa Pig episode banned in Australia?

The episode of Peppa Pig called “Mister Skinny Legs” came out in its first season, in 2004. This particular episode indicated that spiders are friendly and there’s no reason to fear them. It’s a good reminder not to be afraid of things just because they exist as “scary” in the public imagination. In fact, the episode points out that most spiders and small and can’t hurt you.

When a spider enters Peppa Pig’s room, her dad explains that there’s nothing to be afraid of and lets the little piglet pick it up and tuck it into bed with her.

This simply did not fly in Australia. You know, the place where spiders are not all small and can be very harmful.

The Guardian (cited below) revealed:

“This advice from the British-produced show was deemed to be ‘inappropriate for Australian audiences’ and the ABC banned it from future broadcast. The episode had not been broadcast on TV because of its unsuitability, but was ‘accidentally published online due to a technical problem,’ the ABC said at the time.”

They also mentioned that “Data released in January revealed 12,600 people were admitted to hospital for spider bites between 2000 and 2013.”

The second banning of Peppa Pig

When the episode aired on Nick Jr years later, parents wrote in with complaints. Nick Jr pulled the episode from the air again.

The episode is a mere 5 minutes long, but parents felt it posed enough of a danger that they didn’t want their kids encouraged to see spiders as their “friends.” — WTF fun facts

Source: “Peppa Pig ‘spiders can’t hurt you’ episode pulled off air in Australia – again” — The Guardian

WTF Fun Fact 13179 – Military Dolphins

Dolphins’ intelligence and biological sonar make them a valuable asset to many of the world’s military organizations, including the U.S. In fact, Naval Base Kitsap uses military dolphins to protect roughly 25% of the country’s nuclear stockpile.

What are U.S. military dolphins?

The dolphins are part of the U.S. Navy Marine Mammal Program, which used dolphins for the first time during Vietnam. The details of the program are secret. But we do know that both dolphins and sea lions are trained for different types of tasks. They’re used for recovery missions, defense tasks, and mine clearing.

At Naval Base Kitsap, the dolphins protect the harbor from weapons tethered to the ocean floor or buried beneath the sediment. Their innate sonar helps them detect these objects. They’ve been trained to return to their handler with a warning signal when they find one. Even more impressive is the fact that the trainer then gives the dolphin a tool (a buoy) to mark the spot where the weapon was found. That way, passing ships can avoid it, and Navy divers can dismantle it.

And when the threat is a human diver who means harm to the base, dolphins are trained to use their mouths to attach the buoy to them, which pulls them to the surface for capture.

Washington state’s nuclear dolphin protection

According to Military.com (cited below), “Since Bangor, Washington, now houses the largest single nuclear weapons site in the world, it needs protection from all sides, including the seaward side. That’s where the Navy’s dolphin pods and sea lions come in. Navy spokesman Chris Haley says the animals have been defending the waters around the stockpile, holding roughly 25% of the United States’ 9,962 nuclear warheads, since 2010.“

The former Soviet Union is believed to have trained dolphins for military purposes as well. The program is suspected to be ongoing in some sense. However, it’s also thought that much of it was sold to Iran during the fall Soviet regime. — WTF fun facts

Source: “Militarized Dolphins Protect Almost a Quarter of the US Nuclear Stockpile” — Military.com

WTF Fun Fact 13165 – The Power of Trees

Behold the power of trees! In 2015, a study found that having more than 10 trees on their block made people feel as healthy as if they were seven years younger or made an additional $10,000 a year.

The healing power of trees

According to the Washington Post (cited below): “After analyzing two sets of data from Toronto, researchers report that adding just 10 trees to a single city block could improve how healthy a person feels as much as if that person made an additional $10,000 a year or were seven years younger.”

The study also found that people who lived in neighborhoods with more trees were less likely to have hypertension, be obese, or have diabetes. This was true across all demographic and socioeconomic groups, so even trees in a less affluent neighborhood seemed to work their magic on residents.

Of course, this doesn’t mean there’s a causal link between trees and health. This could just be a correlation. But trees not only affected people’s objective health measures but their perceptions of their well-being as well. We feel better around trees.

Perhaps this is why the Japanese art of “forest bathing” is being explored in relation to cancer treatment.

The study looked at 30,000 people in Toronto, which has universal healthcare. That’s important because access to healthcare is not as reliant on one’s socioeconomic status, so it controls for that factor.

Why are trees good for us?

While the correlation found in the study was strong, the researchers still don’t know why trees make us healthier. One possibility is their ability to remove pollutants from the air.

And the more we learn about the effects of air pollution on our overall health, the more sense that makes. However, there are other studies that show even a short time spent among trees can have beneficial effects on our health. — WTF fun facts

Source: “10 more trees on your street could make you feel 7 years younger, study shows” — Washington Post

WTF Fun Fact 13161 – Bats Give Birth Upside Down

Female bats give birth upside down and catch the baby in their wings.

Interesting facts about bats

We know bats sleep upside down, but we weren’t aware they did much else that way. And you can chalk that up to our clear lack of knowledge about anything bat-related. But thanks to Montana’s Public Radio station (cited below) and their show “Field Notes,” which is produced by the Montana Natural History Center, we now know a lot more!

For example, did you know bats only breed when it’s rainy? Or share the responsibility for nursing baby bats among colony members? Or that the “colony” is actually called a “harem”?!

It turns out that female bats are only fertile during the wet seasons. That’s January or February in the Southern Hemisphere, or March or April in the Northern Hemisphere.

They divide themselves up into harems, territorial groups with one central male bat. However, that bat doesn’t father all the bat babies. Female bats in the harem may mate with other male “harem leaders.” Interestingly, the bat experts note that “it’s very unlikely that they will mate with a non-harem male.” So any lone bats out there are out of luck.

Apparently, the smaller the bat is, the more likely he is to be successful in reproducing. That’s because the males don’t simply go around and mate with harem members at will – they have to work for it. Males have to attract females with a display of flying and hovering prowess. Big bats can’t hover as well.

According to Field Notes, “Smaller males are more successful fathers because they can maneuver more nimbly in the air. Not only can they hover well and display themselves to females, they can maneuver well during actual mating, which happens – you guessed it – upside down.”

How do bats give birth upside down?

Ok, so that’s already more upside-down time than we had imagined.

But what about birth?

Females have only one baby per pregnancy, and those babies gestate for three months. When they are ready to give birth, the mother bat hangs upside down by her feet (occasionally grasping a ceiling or branch with her hands as well). This might sound like a lot of work, but when a bat’s feet grasp something, they are actually at rest (unlike ours). So it would take more energy to be in any other position.

Eventually, the baby bat emerges feet-first and they can even grasp their mother’s fur to pull themselves out. That’s helpful!

The mother then uses her wings to ensure the baby doesn’t fall from whatever she’s hanging from.

Not only do mothers nurse babies upside down, but they even take them on hunting trips when they’re not in baby bat daycare (or small groups of young called “creches”).

The mother bats nurse their young until two weeks before they’re weaned. At this point, they may let other mother bats nurse their babies.

And a final interesting fact – female bats are favored by mothers and more likely to survive. — WTF fun facts

Source: “Bat Moms Do A Lot Of Hanging About” — Montana Public Radio

WTF Fun Fact 13158 – Baby Puffins

Baby puffins are called pufflings. How adorable is that?

A stranger fact about baby puffins

Ok, now that you know pufflings exist, did you know that on Iceland’s Westman Islands (aka Vestmannaeyjar), puffling season means throwing the animals off cliffs? We promise it’s not what it sounds like.

People do it to save their lives.

According to NPR:

“The chicks of Atlantic puffins, or pufflings, hatch in burrows on high sea cliffs. When they’re ready to fledge, they fly from their colony and spend several years at sea until they return to land to breed, according to Audubon Project Puffin. Pufflings have historically found the ocean by following the light of the moon… Now, city lights lead the birds astray.”

Now, some of the residents of Vestmannaeyjar “spend a few weeks in August and September collecting wayward pufflings that have crashed into town after mistaking human lights for the moon. Releasing the fledglings at the cliffs the following day sets them on the correct path.”

So they don’t chuck them off cliffs (although some may toss them less gently than need be) – they just lead them back to where they belong (or have a better chance of surviving). It’s amazing how light pollution can disrupt an ecosystem!

Puffling lives

Since a pair of puffins mates for life but only raise one egg per season, the loss of a whole generation could be devastating to their populations.

You could even get a chance to help save the pufflings if there’s a colony around you. Their seasons will depend on food supplies and light conditions.

If you decide to go on Puffin Patrol, it’s best to search for them at night with a flashlight in places where they might find food. It sounds like a great reason to go on vacation from August through September! — WTF fun facts

Source: “Puffin Chicks” — Audobon Project

WTF Fun Fact 13156 – Fish Cough

Fish can cough. But they don’t sneeze. Pretty riveting stuff, right?

Well, it turns out it is pretty interesting.

How do fish cough?

While a fish can cough, it doesn’t make a sound when it does. As the experts at Fluffy Planet explain:

“Every now and then, a fish uses its gills to extract a little amount of oxygen you find in the water. Then, it releases gases like carbon dioxide. During this process, it is possible for particles or bacteria to get sucked in through the gills. Similar to how bacteria and particles are sucked into our mouth while we are breathing.

To clear the bacteria and particles, our body will either instinctively cough, or you could be prompted to cough on your own to clear out these particles. So, when these particles go into a fish’s gills, their ventilation cycle is interrupted with a cough.”

The coughs happen when the fish’s ventilation cycle is interrupted as they need to clear out their gills.

But while fish can cough, they can’t sneeze. And they don’t cry. It’s simply not biologically possible.

Why can’t fish sneeze?

We use our throats to cough, and it’s an action that clears us out. But sneezing requires air to be expelled involuntarily in response to an irritant. Sneezes expel air from the lungs at great speed. And since fish live underwater, they don’t breathe air (and don’t have a version of lungs like ours). If they did, they would float when their lungs will with air.

Now, you probably know fish don’t cry (they can’t really produce tears underwater), but you might find an article from the New York Times interesting. It explains that researchers think fish can get depressed. When they do, they exhibit similar behavior to humans, such as isolating themselves. — WTF fun facts

Source: “Do fish cough, sneeze, or cry?” — Fluffy Planet

WTF Fun Fact 13149 – Spiders Recycle Their Webs

Not all spider webs are destroyed with a broom. In fact, spiders can recycle their webs by eating them!

How and why do spiders recycle their webs?

Some spider webs are built to last years while others only last a day or so. Of course, while those beautifully spun webs in the corner of your attic may have been built as a long-term home for the spider, in that case, their duration is influenced by how long humans allow them to stick around.

But for some neglected spider webs, they can be so enduring that a new generation of spiders might come to reside there.

More fragile webs may only last a day because spiders build them simply to catch food. Rain and pollen may affect their stickiness. In these cases, spiders will pack up a web for the day and build again the next. When this happens, spiders often eat their webs to recycle the amino acids that made up the silk protein used in web construction.

It’s an impressive feat since webs can consist of 65 feet of silk!

Not all spiders ingest their silk though. And some use it to wrap their eggs sacs. But considering how much energy it takes to weave a web, it’s not all that surprising that spiders recycle webs by eating them in some cases.

Spider web building

Spider web silk is made out of protein chains. And some of it is as strong as kevlar (though obviously it’s not as tightly woven, so we hardly notice when batting them away). In fact, scientists are studying it in the hopes of making future body armor!

Spiders typically start building webs by pulling silk from a gland in their fourth leg. The fourth leg on the opposite side contains even more silk glands. Then, in order to begin, the spider (depending on the species) can shoot it out to attach to an object or wait for a breeze to carry it to the base from which it will start building.

From there, the spider will typically create a number of attachment lines. Then they decide which are the strongest and begin weaving from there. Different spiders have different web patterns. In fact, they’re so distinct that experts can look at the structure of a web and tell you precisely which type of spider built it.

— WTF fun facts

Source: “Why do spiders eat their own webs?” — Discover Wildlife

WTF Fun Fact 13143 – Grass Screams When Cut

You’ll never cut your grass again without thinking of this weird fact – grass cries for help when it’s mowed. No, you can’t hear it, but scientists have discovered grass screams when cut.

How does grass scream when cut?

We’re only just beginning to understand how plants communicate with one another and the rest of the world around them (including insects).

Dr. Michael Kolomiets, a Texas A&M AgriLife Research plant pathologist, published an article in 2014 in The Plant Journal noting that the aroma of cut grass is the plant’s way of both signaling distress and attracting beneficial insects that will help it heal.

According to ScienceDaily (cited below): “When there is need for protection, the plant signals the environment via the emission of volatile organic compounds, which are recognized as a feeding queue for parasitic wasps to come to the plant that is being eaten and lay eggs in the pest insect,” Kolomiets said.

Plant communication

Grass produces a “defensive” protein when damaged. Of course, that doesn’t stop the lawnmower or insects from destroying the blades. But it appears to produce a compound that repels insects that are feeding on the damaged grass.

This compound, or one related to it, also appears to attract organisms like parasitic wasps that feed on insects like caterpillars that are destroying the grass.

Or to put it in science-speak:

“We have proven that when you delete these volatiles, parasitic wasps are no longer attracted to that plant,even when an insect chews on the leaf. So this volatile is required to attract parasitoids. We have provided genetic evidence that green leafy volatiles have this dual function — in the plant they activate production of insecticidal compounds, but also they have indirect defense capability because they send an SOS-type signal that results in attraction of parasitic wasps.”

So, maybe it’s not so much that grass screams when cut so much as it cries for help. Either way, freshly cut grass emits a compound that repels damaging insects and attracts insects with a protective function.

It’s just one of the many ways that plants are far more complex than we had ever previously imagined. — WTF fun facts

Source: “Mown grass smell sends SOS for help in resisting insect attacks” — ScienceDaily