49 Facts I Learned This Year That — Surprisingly — Like, A Lot Of People Don't Know
Several times this year, I shared lists of "little-known facts" — aka facts BuzzFeed readers and Redditors alike revealed that most people either get wrong or, for whatever reason, are simply never taught.
So you can enter 2025 even smarter than you were in the beginning of 2024 (which I'm willing to bet is already pretty dang smart!), I rounded up the commonly unknown facts people taught us this year:
As always, to keep this list from being ten thousand pages long, these are only summaries and by no means exhaustive explanations on all these topics. If you'd like to do a deep dive of your own, sources are linked out for each fact. Happy learning! 🤓
1."The human body glows in the dark. No, seriously. It emits visible light at all times, but our eyes are too weak to see it. So yeah, you’re glowing right now, but no one can appreciate it."
2."It took a long time for the Giant Tortoise to be scientifically recognized because to be catalogued, a sample had to reach London. Turtles turn out to be really, really good to eat."
The Galápagos Tortoise's discovery can be traced to Spanish sailors as far back as 1535. However, they proved to be really convenient meals for long ship voyages, as the tortoises could live on ships until they were needed, were large enough to feed many, and — above all — were apparently really delicious. William Dampier — a 17th-century pirate — said of them, "The land-turtles are so numerous that five or six hundred men might subsist on them alone for several months, without any other sort of provision. They are extraordinarily large, fat, and so sweet that no pullet eats more pleasantly."
Centuries later, in 1835, Darwin would go on to develop his theory of natural selection inspired by the Galapagos and the several different species of giant tortoises amongst the islands, though he and his crew, too, ate some of the tortoises that would prove to be essential evidence.
3."Your skin doesn't have receptors to let you know if it's wet or not. This is why those sensory deprivation tanks have you floating in it. When the water is warm enough, your skin stops sensing the 'wetness' and you just feel like you're floating in the air."
—ZorroMeansFox and Nutzori
4."The difference between less and fewer. 'Fewer' is used when something is countable, ie: Bob has fewer apples than Sally. 'Less' is used when it’s not, ie: Bob shows less kindness to horses than Sally.'"
—u/trigunnerd and u/not_thrilled
5."That butterflies retain memories from their larval (caterpillar) form. So while it is all goo in the pupa form, something is keeping some memories intact."
Scientists discovered this through a study where they trained caterpillars to avoid certain smells by giving them a mild shock when near them. The moths that the caterpillars turned into knew to avoid the odors, suggesting that they retained the memory through their metamorphosis, despite their brain and nervous system being dramatically reorganized during the process. You can read more about it here.
6."If there are 23 people in a room, the probability that two people have the same birthday is over 50%."
This is called the birthday paradox. It involves a bit of math, so bear with me here. If every single person compares their birthday with each of the 22 other people in the room on a 1-on-1 basis, there are 253 possible combinations of people. In general, any two people have about a 99.7% chance of not having the same birthday. To calculate the likelihood of no birthday matches in that group overall, you'd multiply that percentage by itself (99.7% x 99.7%) 253 times (aka the number of possible combos), which ends up being 49.95%. If there's a 49.95% chance of them not having the same birthday, that means there's about a 50% chance of them having the same birthday! You can take a closer look at the math yourself here.
7."There's a thing called the Royal Order of Adjectives. This rule dictates the specific order in which adjectives should be arranged in a sentence, and native speakers follow it instinctively without being taught."
The order is: quantity, opinion, size, age, shape, color, origin/material, and qualifier. For example: A lovely small old square brown French leather handbag. It sounds wrong if you deviate from this order, but many people aren’t consciously aware of it! When you say something like 'A lovely small old square French leather brown handbag,' other naive speakers will wonder what French leather is. "
8."I remember reading that if you look at pictures of sick people, your immune system will automatically give itself a little boost just by looking at the pictures."
According to National Geographic, Mark Schaller from the University of British Columbia did a small study looking into this. What he found was that people who looked at pictures of people sick or sneezing "had a stronger immune response to later infections" than people who hadn't looked at such photos. The logic behind this is that, much like an emotional reaction you might have to an image like that of feeling gross or unclean, your brain and immune system also react. Subconsciously, you might be on high alert now thinking about it, and avoid coming into contact with a possible contaminant. This is a behavioral reaction. He also suggests our immune systems may react to these images as well, and give us a boost in anticipation of illness or potential threats. You can read about this more in-depth here.
9."The story of Humpty Dumpty doesn’t explicitly state that he is an egg."
The assumption that Humpty Dumpty is an egg can actually be traced back to Lewis Caroll's Through the Looking-Glass, in which Alice sees a large egg with human-ish features and declares that it is Humpty Dumpty.
It is, in fact, believed by some — and allegedly has been confirmed by some military historians — that Humpty Dumpty was the name of a Royalist cannon in the English Civil War that sustained damage in battle and was unable to be repaired.
10."UTIs in the elderly can cause them to hallucinate or be disoriented."
Older patients with UTIs tend to have untraditional symptoms. They often experience symptoms such as delirium, tachycardia, frequent falling, or — in more extreme cases — hallucinations.
11."Rabbits don't have paw pads like cats or dogs. They've got nothing but fluffy feet. If you see a cartoon rabbit with paw pads, it's all lies."
12."Sign language isn't universal. Sign languages are their own unique languages, not just a signed version of spoken language."
There are, in fact, around 300 different sign languages. Different countries have their own sign languages as well, which vary even if the "base language" is the same. For instance, both American and British sign languages are based on the English language, but they are two entirely different sign languages. Languages can also vary regionally and culturally, like dialects or accents do in spoken language.
13.Humans have stripes. We just can't usually see them. They're called Blaschko's lines, and according to the American Osteopathic College of Dermatology, they're patterns on "the skin that represent the developmental growth pattern during epidermal cell migration."
Suggested by: Probablynotspiders
14.St. Patrick was not, in fact, Irish. Despite being the patron Saint of Ireland (and St. Patrick's Day generally being a celebration of Irish pride and culture), St. Patrick was actually born in Scotland. He ended up in Ireland after being kidnapped by Irish pirates and kept as a shepherd.
After six years, he escaped and returned to Britain, then supposedly had a vision that told him to return to Ireland as a Catholic missionary — which he did. He converted thousands of Irish to Catholicism, aka where the "patron Saint of Ireland" title comes from and the assumption that he's Irish himself. You can read more about him here and here.
Suggested by: u/HacksawJimDGN
15."The first English scientists to receive a preserved platypus were so absolutely 100% convinced it was a hoax that he nearly took the specimen apart trying to find evidence that it had been assembled from multiple different animals."
It's true! In 1799, zoologist George Shaw — the first to publish a description of a platypus — said of the animal, "It naturally excites the idea of some deceptive preparation by artificial means..."
16."The fax machine was invented in the 1800s, well before the telephone."
It's not the fax machine we know today, but the "original" fax machine (aka the electric printing telegraph) was invented in 1843 by Alexander Baine. In contrast, the telephone was invented decades later in 1876 by Alexander Graham Bell. Big century for Alexanders, it seems!
17."A pony is not a baby horse. A baby horse is called a foal. A pony is a horse that as an adult is below a certain height."
Size-wise, a pony is usually under 14.2 hands high as an adult. They mature to their full size more quickly than horses do, too.
18."Zebras are black with white stripes."
Though they might look like they're white and have black stripes at first glance, underneath their fur, zebras have dark skin. They grow both black and white fur, and their black fur gets its color from melanocyte cells. Their white fur has deactivated melanocytes, which means that active melanocytes — or black fur — is their "default" color, thus making them black with white stripes.
19."Words that are spelled the same but pronounced with emphasis on different syllables are actually indicative of the part of speech they are. Stress on the first syllable is a noun. Stress on the last syllable is a verb. Examples: CON-tract and con-TRACT. The former is a noun (sign this contract), whereas the latter is a verb (the muscles contract). Same with record, address, impact, object, and a few others."
20."There's a jellyfish that doesn't have an anus! Whenever too much waste product builds up in its body, it simply makes a hole somewhere on its body, discharges the waste, and then the hole closes back up again."
This is the warty comb jelly, the only creature we know of that does this. When it has to go, part of its gut fuses with the outer layer of its "skin," which creates a hole that is then immediately sealed back up. Adult warty comb jellyfish do this about once an hour.
21."The fact there are multiple ski resorts in Australia. Always seems to blow people's minds."
Parts of Australia, like New South Wales, Victoria, and Tasmania, do get snow during their winter months of June, July, and August, so you absolutely can go skiing there! And speaking of Australia's winter months...
22."We all know the dinosaurs died out a long time ago (~65 million years ago). But what's even longer: they roamed the Earth for 165 million years. The Stegosaurus went extinct 66 million years before the T-Rex even existed."
23."The Children's Crusade was a Holy Crusade made up nearly entirely of children. Their goal was to siege and take the Holy Lands for the Catholics, fixing their fathers' and brothers' perceived failures and taking the city. Most of them died before getting anywhere out of Europe."
The Children’s Crusade of 1212, led by 12-year-old Stephen of Cloyes, was approved by neither King Philip nor the Pope, but that didn't stop Stephen and his army of children (which, according to legend, was as large as 30,000 people). Another similar group of child crusaders formed in Germany, led by Nicholas of Cologne. They supposedly carried crosses and banners instead of weapons and optimistically believed they could convert people through their words and divine intervention. As OP mentioned, the Crusaders hit a wall, so to speak, around the time they made it to Genoa, Italy, as many grew tired, hungry, and did not speak the language. The groups fell apart when they hit the coastal cities, where they were supposed to wait for boats to the Holy Land. You can read about them more in-depth here.
24."Poison dart frogs are only poisonous if you feed them toxic bugs. They are perfectly safe to handle if you feed them crickets."
The poison dart frog is considered to be one of the most toxic animals in the world. Scientists believe the bugs poison dart frogs eat — like formicine ants —are what make them so poisonous. So, zoos feed poison dart frogs a different diet —namely, crickets or fruit flies — which allows zookeepers to handle the frogs without the risk of being poisoned. There's currently no treatment or antidote for their toxins, too.
25."Babies have more bones than adults. A lot more."
Babies are born with about 300 bones, whereas adults have 206 bones. As babies get older, some of their bones begin to fuse together. For instance, babies tend to have soft spots on their heads, which feel a lot different than the hard heads we adults have. Well, as babies age, those soft spots "close up" as the bones in their head fuse, giving them the skulls we have as adults. You can read more about the process here.
26."Froot Loops are all just one flavor."
Despite the various colors, Froot Loops are reportedly all one flavor, which is a blend of orange, lemon, lime, apple, cherry, raspberry, and blueberry. Fun fact: Trix and Fruity Pebbles — two other rainbow, fruity-flavored cereals — are also just one flavor.
27."Animals can see completely different colors than us. Pretty wild when you think about it."
Many animals can see colors that we as humans cannot. For instance, birds, reptiles, honeybees, and some bony fish have the ability to see ultraviolet light, which is outside our range of "visible light." Though humans and bees can both be looking at the same flower, for example, we're seeing them in different ways and colors. On the flip side, some animals, like dogs and cats, see fewer colors than we do and see them more weakly.
28."Previously fish-free lakes and ponds can be populated by fish thanks to migrating ducks. When ducks eat fish eggs, some of them can pass through the digestive system unharmed and hatch in new waterways."
29."Uppercase letters are called that because they could be found in the upper drawer of a printing press, lowercase could be found in the lower case of the printing press."
Before the printing press, they were called majuscule and minuscule, respectively.
30."Rollercoasters are built to shake! I’ve seen so many people decide not to get on because of the swaying, but it’s important! If the support beams and tracks didn’t shake, they’d simply snap with all the force from the coaster cars roaring over them."
31."Also, roller coasters — at least the traditional kind — don’t have any engines. Typically, there’s a slope at the start where a chain in the track pulls the cars up to the top. After that, it’s all gravity and momentum. Takes some careful design to ensure that the cars don’t run out of (metaphorical) steam before the end."
32."German chocolate cake was made by an American named Samuel German. Not an actual German."
33."Flamingos get their pink color from the seafood they eat. Change the food, and they'd be a different color."
According to the National Zoo, flamingos get their pink color from the carotenoids in their food — particularly, from microscopic algae and brine shrimp.
34."Deoxygenated/venous blood isn’t blue, it’s dark red."
You might've been taught as a child that the blood flowing through your veins is blue because it hasn't been exposed to oxygen. That, however, is a myth. It's actually a dark red color. When you look at a vein in your arm, for instance, it only appears blue or purple-ish because you're viewing it through layers of fat and skin.
35."That your car’s fuel gauge has a little arrow next to the gas pump icon indicating which side your gas cap is on. Super handy when driving a rental or a new car."
36."There are more bones in gummy worms than real worms."
A common ingredient in gummy worms (unless specified to be vegan) is gelatin. Gelatin is made from animal bones, skin, and cartilage, which are processed for their collagen. Real worms have no bones, as they are invertebrates and actually have a hydrostatic skeleton. So, it looks like gummy worms really do have more "bones" than real worms do!
37."The term 'bug' in computing has been around for a long time. The term was not commonly used until an actual bug landed on an electrical switch, causing the computer to malfunction. The term bug grew in popularity afterward and landed us where we are today. Also, when we find a bug in software, we apply a 'patch.' This comes from old cardex/punch card systems. If a punch card was punched in the wrong spot, you could fix it by applying a patch to the hole."
The use of the term 'bug' to refer to an error or glitch can be traced all the way back to Thomas Edison in the early 1800s. As OP said above, it gained popularity in computer science after 1947, when a team at Harvard discovered that the reason their computer (Mark II) was having consistent errors was because an actual bug — a moth — had gotten inside the hardware and was messing with its functionality.
38."There is a jellyfish that is 'immortal.' It returns back to pupa state and then again grows and repeats the cycle!"
Turritopsis dohrnii, aka the Immortal Jellyfish, can transform back into a polyp (the "child" phase of a jellyfish's life cycle) when they're physically damaged or starving. Essentially, the jellyfish "shrinks in on itself" and reabsorbs its tentacles, becoming a blob that soon transforms into a new polyp. From that, it matures and the new "medusae" buds off of it. The process is called transdifferentiation. You can read more about it here.
39."I recently learned that goodbye is a shortened form of 'God Be With You,' which people in Ye Olde England would say to each other."
40."The word 'set' holds the record for having the most definitions of any single word."
According to Guinness World Records, there are 430 different definitions for the word 'set' in the 1989 Second Edition of the Oxford English Dictionary. In fact, the entry is 60k words.
41."The release of all of the original Star Wars trilogy is closer in time to WWII than the present day."
The first film in the original Star Wars trilogy came out in 1977. WWII ended in 1945, which means they are 32 years between them. If you want to take this to extremes, though, the final film in the trilogy — Return of the Jedi — came out in 1983, which is 38 years after WWII ended. It's 2024 at the time of my writing this article, which means there are 47 years between the first film of the trilogy and now and 41 years between Return of the Jedi and today. So, yeah, the math is mathing!
42."Water towers are for water pressure, not just a town putting its name on a tank and saying, 'Hey, look how much dang water WE have.'"
"They also store water to compensate for peak demand hours. This prevents the pumps from switching on and off frequently."
43."Your pee is filtered out of your BLOOD by your kidneys. There's no direct route for that glass of water from swallow to kidneys to pee (like food/feces has it's own set of pipes, from in to out). Water goes into your blood circulation (absorbed through the gut) and at some point, it gets lifted by your kidneys (along with other waste products) via your blood."
"It probably sounds breathtakingly obvious to many of you, but I teach A&P as part of my job, and many people don't initially realize that. They assume that there's some separate tube that takes fluids direct to the kidneys because they've just never really thought about it."
44."Trees get the vast majority of their mass from the air. All that wood? That was once carbon dioxide and sunlight."
45."The component parts of the word helicopter are not 'heli' and 'copter.' It’s 'helico,' meaning 'spiral-shaped' like the word 'helix,' and 'pter' meaning 'wing' as in 'pterodactyl.'"
46."The tune of the ‘Alphabet Song’ is actually the ‘Twinkle Twinkle Little Star’ tune."
47."Plumbing comes from the root Latin word of 'plumbum', which means lead, and is the reason it's Pb on the Periodic table. The Romans made water pipes out of lead."
48.Most of the oxygen we breathe doesn't actually come from trees. When you were in school, you probably learned about how trees and other plants use carbon dioxide — what we breathe out — in the process of photosynthesis, which creates oxygen — what we breathe in — as a byproduct. People often assume that most of the oxygen we breathe comes from trees or other plant-dense forests, but that's not true. According to National Geographic, only about 28% of oxygen on Earth comes from rainforests.
The majority of it — somewhere between 50% and 85% — actually comes from marine plants, like kelp and phytoplankton in the ocean. You can read more about it here.
Suggested by: u/duckyoumate
49.And lastly, "That sharks are older than the rings of Saturn."
Saturn's rings are estimated to be no more than 400 million years old. Comparatively, sharks date back to the Late Ordovician Period, or about 450 million years ago.
Do you know any little-known facts like these? If so, please share them with us in the comments below! They just might end up in a future BuzzFeed Community post!
