There’s more to our wonderful world than any single person could ever know. When one Reddit post asked people to share facts that they thought nobody else knows, the rest of us got a great list of curiosities from around the world.

Did you know, for example, that dolphins can be trained to perform military aquatic guard duty? Or that grass only evolved once dinosaurs were practically extinct? There are plenty more fascinating facts in this list, so scroll on and learn something new!

#1

The "dog days of summer" refers to the time of the year when the dog star, Sirius, is brightest in the sky.

Image credits: anon

#2

I don't think most people know the meaning of "prodigal." They know the parable of The Prodigal Son and think it refers to someone that leaves and then has to come crawling back, but that's incorrect. "Prodigal" means to spend money lavishly or wastefully. The prodigal son was prodigal whether or not he ever went back to his father.

Image credits: onlytoask

#3

Greater one-horned rhino or Great Indian rhinoceros population stands at around 3,700 individuals, a significant increase from around 200 remaining at the turn of the 20th century. Strict protection and management action from Indian and Nepalese authorities and their partners are responsible for bringing the species back from the brink.

The Great Indian rhinoceros is definitely a conservation success story in the making, but there are still other species of rhinoceros that are at great risk of going extinct. Only about 60 Javan and about 200 Sumatran rhinoceros are thought to exist in the wild.

Image credits: SuvenPan

#4

Sharks have been around longer than the rings of Saturn.

That’s right! Current estimates suggest that Saturn’s rings are about 400 million years old, while sharks evolved roughly 450 million years ago. Interestingly, that also makes sharks older than trees and grass.

Modern humans been around for about 200,000 years. Humans about 6 million. We were in a stone age for about 2.6 million years.

We were not the first to use stone tools. There was another species, probably a close cousin, that used them about 700,000 years before the first human.

Chimpanzees and some other animals are currently in a stone age.

Dinosaurs died out 65 million years ago. Triceratops were probably the last species to die out.

Grass didn't evolve until 66 million years ago (iirc) so only the last of the dinosaurs saw grass.

Tyrannosaurus and triceratops lived closer to us (65 million years) than the stegosaurus (80 million years).

I have more. I'm full of useless facts.

Image credits: kingferret53

#5

A second is called a second because it is the 2nd division of the hour by 60 (pars minuta secunda), the 1st division being a minute (pars minuta prima).

Image credits: edlee98765

#6

Gary Numan was born two weeks before Gary Oldman

Image credits: steve0suprem0

#7

Hans Zimmer was the keyboard player on "Video Killed The Radio Star"

Image credits: Kryodamus

#8

The tongue on a woodpecker wraps around its brain as a form of soft insulation when it hammers. Then the tongue is able to extend far into the tree to retrieve bugs when it isn’t hammering.

Image credits: anon

#9

The spotted salamander is the only vertebrate that photosynthesises.

Believe it or not but this fact gets even more interesting. The yellow spotted salamander uses photosynthesis in the embryonic stage. It does this by forming a symbiotic relationship with algae, which produces oxygen to feed the embryo as it develops and receives the embryo’s waste products and carbon dioxide. Researchers have even found algae inside the embryo’s cells!

Image credits: Centuri42

#10

Boanthropy is a psychological disorder in which a person believes they are a cow and try to live their life as one. Medical explanations suggest late-stage syphilis as one of the causes? Cool

Image credits: j451k4

#11

Sarah Winchester (who built the “Winchester Mystery House”) was not into the occult, wasn’t afraid of evil spirits, and didn’t think she could live forever by continuing construction of her house - or, at least there is no evidence to support that. People who knew her said she was a devout Christian and would never have anything to do with the occult. The stories about spiritualism and paranoia are for the tourists. She probably just liked having workmen around and a little activity going on at the house - she was one of the richest women in the world, so she could do as she pleased. Some who knew her said she may have done it to keep locals employed. Far from being afraid of stopping construction, one of her letters mentions that she halted construction due to excessive heat out of concern for the workmen.

It’s interesting how BS can just take the place of reality if it’s repeated often enough.

#12

Before being born, two of the four chambers of a baby's heart are not used, they're actually bypassed!

There's no need to pump de-oxygenated blood to the lungs when in the womb, because the lungs aren't breathing air yet, and so are not supplying oxygen. All the oxygen comes from the umbilical cord.

So the two chambers responsible for sending blood to/from the lungs are (largely) bypassed.

Image credits: whomp1970

#13

The nuke stockpile in Washington State is guarded by trained dolphins that seek out and clamp a balloon on unfamiliar divers.

Image credits: Gothsalts

#14

Big Ben is the Bell not the clock or tower.

Image credits: anon

#15

More pigeons have war medals than horses, dogs or mules

Image credits: Global-Program-437

#16

Raindrops don’t fall in the drip shape popularly conveyed. They fall in the shape of tiny parachutes or hamburger buns.

Image credits: CBGville

#17

Many species of shark have seven senses, most notably the ‘man eaters’ (I despise that term) Tiger, Bull, and Great White.

In addition to the traditional five, sharks also possess ampullae of lorenzini (gel-filled pores on their snout - think of the black freckles on a Great White) that detect electrical impulses such as spasmodic movement in water and ambient electrical fields, and the lateral line (a thin organ running down their sides) that acts as a magnetic detector, which allows the shark to orient itself in real time to the earth’s magnetic field, giving it a sense of direction akin to that of a bird.

Great Whites additionally are coated in denticles. Despite their smooth appearance, their skin is actually extremely rough and toothlike. Think of sandpaper on some serious steroids. A Great White bumping into you can actually peel layers off you like a potato peeler. That’s if they don’t give you a bite of course!

On to that, despite their fearsome reputation, Great Whites don’t care for humans as a food source. They need immense amounts of blubbery fat and meat like whales and seals can provide, we’re simply too lean for them to get much nutrition. Most attacks are down to either territory being defended, or simple mistaken identity. They’ve got terrible eyesight, so a human on a boogie board looks exactly like a seal from below. And, as they have no hands, biting is the only way they can be sure of something. It just sucks for us that that’s typically fatal.

Finally, if you ever get a moment, look up spy hopping. Sharks can and will pop their heads above water to get a lay of the land. It’s frightening to behold.

Image credits: ReaverRogue

#18

There are at least three people who were born before the Wright Brothers took their first flight at Kittyhawk who were still alive when the Mars Rover died.

When they were born, humankind was stuck on the ground. In their lifetime, they saw single person flight, then military flight, intercontinental flight, a (gasp) female pilot, commercial flights, supersonic flight, space flight, humans on the moon, a probe sent out of the solar system, a robot cruising around on an entirely different planet picking up rocks, and finally that robot had been there so long it died. All in their lifetime.

That's just crazy to me.

#19

Opossums are extremely unlikely to have rabies. They have a lower body temperature than most mammals and it makes them an unsuitable host for rabies.

Opossums are fascinating creatures, and not only because they have a high resistance to rabies. Scientists believe that they were around at least as far back as the extinction of the dinosaurs, and they are also the only type of marsupial native to the US.

#20

The Earth's rotation is slowing down, and we soon will have more than 24 hours in a day (well, soon, geologically speaking...).

As the Earth slows and extends the length of its days, we can consider what a “day” looks like on other planets in our solar system. The shortest is Jupiter at a zippy 10 hours and the longest is Venus at a painfully slow 5,832 hours. The closest day to hours is on Mars (25 hours).

Image credits: toucanfrog

#21

Rabies kills around 60,000 people globally every year. To date, only 14 people worldwide have been known to recover after developing symptoms.

Rabies is as deadly as it is because it targets our central nervous system and destroys our body’s ability to perform essential functions. However, it does have a moderately long incubation period. If a bite victim is treated with the vaccine within 10 days of being bitten, they can expect to survive, but by the time symptoms appear, it’s already too late.

Image credits: Johhnymaddog316

#22

The girl who voiced Lilo in Lilo and Stitch also played Samara in The Ring, both released in the same year (2002).

Image credits: ThrowRARAw

#23

Animals and other creatures each perceive time in different ways based on their Critical flicker frequency which is almost like their minds refresh rate, dogs for example perceive time as being slower than humans do and it's perceived as a little faster by cats.

This model can be used to describe our perception of time, but most directly, it is a term that reflects how our brains process visual information. A creature’s critical flicker frequency is the threshold at which a rapidly flashing light appears to them as a steadily shining light.

Image credits: TwilightArcade

#24

Concrete can set underwater.

Image credits: cizzoo

#25

Of all the US states, Maine is the closest to Africa. Seriously look at a globe, not just that flat oval map you saw in every classroom growing up. Africa is further north than you think, and Maine is further east than you think.

Image credits: slytherinprolly

#26

A quarter has 119 ridges.

118 on a dime.

Image credits: d2the3

#27

The British trained seagulls to poo on the periscopes of enemy submarines before they realised seagulls can’t fly that far out to sea

Image credits: swallowyoursadness

#28

The original Red Velvet cake didn’t use food coloring. The red color was a result of a chemical reaction between vinegar and dutch cocoa powder. It also originally used Ermine Frosting, a boiled milk frosting (which is delicious)

#29

Sara Josepha Hale is the reason for the myth and celebration of Thanksgiving in the United States. She asked President Lincoln in 1863 to champion a holiday that would bring families together in the wake of the U.S. Civil War. The goal was to get people back in each others company to celebrate the nation. She then helped perpetuate a myth of "The First Thanksgiving" to remind the country of how the colonists persevered with the help of indigenous peoples. Seven years later, other Federal Holidays would officially be recognized throughout the country.

Image credits: LDexter

#30

No one has found a centipede with exactly 100 legs, because all centipedes discovered have an odd number of pairs of legs they have found centipedes with 98(49 pairs) and 102(51 pairs) but never exactly 100.

#31

The poem “Ozymandias” by Percy Shelley is based off a statue brought from eygpt by the French, and passed onto the British. The very same statue is in the British museum on full display.

Another cool fact about that statue is all the damage done to it was done *after* it was discovered. They just had such a hard time moving it.

#32

the middle name of Michael J. Fox is Andrew.

Image credits: DieInsel1

#33

The Jews were expelled from Spain in the 1400s. No Jewish children were born again in Spain until 1966.

#34

There was a man, Angus Barbieri who didn't eat for 382 days. He was morbidly obese and lived on tea, water, soda water and coffee while visiting the hospital weekly for vitamin and electrolyte treatments. He lost close to 280 lbs and broke his fast with an egg once he met his goal weight.

Image credits: SurrealEffects

#35

Being in a “higher tax bracket” does not make your take home pay less. That’s not how taxes work.

#36

A couple interesting science facts that lead to in interesting likely somewhat obscure fact about an old kitchen appliance. (Although I did learn this from a YouTube video which currently has 1.6M views, so at least that many other people probably know it)

When you cook something in boiling water, is always cooks at the boiling temperature of water no matter how long it's in there. Once water begins to boil any additional heat you apply goes to converting the water to steam. You can't actually get it any hotter. The hotter you make the fire the faster it boils off, but the liquid water never gets above 212F at sea level.

If you heat a magnetic metal up it will eventually lose its magnetism. If it's an actual magnet, you just permanently un-magnet-ed it. If it's a normal piece of metal though it will just lose the ability to stick to a magnet and that property will return when it cools down. The exact temperature this happens at varies depending on the metal.

Combine these facts together and you can make a nearly perfect automatic rice cooker. Basically you take metal pot and put the appropriate ratio of rice and water in it and set it in the cooker. The cooker has a heating element of a known wattage that heats up and boils the water. The pot will sit right at the boiling temperature of water as long as liquid water remains because the water will be absorbing all the excess energy to turn to steam. As long as you followed directions the amount of time that water will take to boil off is very predictable with the fixed heating element. That will be the appropriate time to cook the matching amount of rice. Once the water has boiled off the pot will quickly begin to heat up. Unchecked this would quickly burn and ruin the rice. However, under the metal pot of the cooker is a button that is being pulled down by a spring but is held against the pot by magnetism from an attached permanent magnet. The button is made from a metal that loses its magnetism just above the boiling point of water. Once all the water boils off the pot starts to heat up and quickly demags the button which gets pulled by the spring and automatically turns off the heat. Perfectly cooked rice through physics.

EDIT: [The video I mentioned](https://youtu.be/RSTNhvDGbYI)