The tailbone has two very specific purposes. The first, is to fracture when you have a fall that lands you on your butt. This ensures that you will be in excruciating pain, regardless of position you stand or lay, sitting on a donut for weeks, as well as being laughed at for breaking your butt. The second purpose, is to haunt you for the rest of your life. The tailbone has declared that it is now fragile, nee, a delicate little flower, and the slightest misstep will cause it to shift its position just enough to make you howl like you've been run through with an invisible sword. It will make you think that you have broke it again. And again...and again. While there haven't been many studies to date, it is believed, by some, that the tailbone is deeply in cahoots with the pinky toe, also known as the Furniture Finder.

"Butt hair" - I can't wait to casually slip the topic into casual conversation. My friends and family have no idea the excitement that awaits them...

"Ear wax is weird and greasy, but it's doing it's job." Me too, earwax, me too.

I'm 50 years old and still have a baby tooth. My adult tooth is up there, patiently waiting for its moment to shine. But it's sorta sideways and will need a little help finding its way when the time comes. In the meantime, this little guy is hanging on like a champ! I figure baby teeth earn interest over time, so I've warned my mother that this thing is going to be worth a fortune when it comes out, and I will be expecting some fat stacks under my pillow! 😆

I'm so happy this channel exists - simply learning. No clickbait, no exaggerations or yelling, just information. Amazing, thank you!

So many different Hanks

I think our personal smell still serves an important purpose: it allows our animals to better identify us

My butt hair theory is that it helps against chaffing. As a girl with thick thighs that are hairless I can say that skin chafing from friction is actually utterly painful.

OH MY GOD THANK YOU! people always say im weird because everyone has their own 'smell' - i have a very sensitive nose combined with a sensory processing disorder, and apparently people cant smell other people?? like, i know who's approaching me from behind because of smell. good to know im not insane lol

Hank flexing on us about how he hasn't died or failed to breed

At 7 (in the late 70's before sonars) they took out my appendix just to realise it was extremely healthy and I was still in really bad pain. They sent my appendix home with me in a bottle, I wasn't too impressed. After a x-ray taken they saw I had two huge cysts on my ovary. I can't remember how they treated it only that one nurse was extremely cruel and refused to bring a bed pan and forced me to walk. I can still remember the pain.

I always assumed butt hair was to help with friction reduction, scent dispersal and ventilation when sweating, passing gas and pooping. I've experimented with this theory a few times by after shaving the hair around my anus. Each time, I ended up devloping pimples between my cheeks, chafed badly, had a buildup of sweat between and at the bottom of my cheeks, had issues releasing gas since the scent bubble literally got trapped between my cheeks and had to roll up and out to escape (the popping of which I could feel on my lower back), and finally, I noticed that I produced much smellier, more forceful, and more audible gas. Regrowing my butt hair got rid of all of the above issues.

Two of my grandparents, grew a third set of teeth after they lost their "permanent" teeth. They were sparse and small, almost like baby teeth.

The butt hair video is surely the greatest intro of all time in the SciShow pantheon.

My theory about our vestigial remaining areas of scant body hair is that it usually is found around openings into our inner bodies… with the exception of underarm hair which simply was left in a protected area . .. my idea is that it served as a sort of deterrent to harmful disease carrying flies and insects and helped to protect our vulnerable body openings .

The doctor removed my appendix during surgery that was for something completely different. He said he removed it as a "precautionary measure." It REALLY upset me!!!

"why do we have butts? it might sound like a cheeky question" " so why would evolution grant us such an ass-et" ooh them puns xd

Unfortunately, I've always had too much fluid and wax buildup in my ears. Ironically, my doctors have instructed me to actually use qtips to wick up fluid and remove excess wax-though they taught me safety techniques so that I wouldn't endanger my ears in any way. So, that age old never use a qtip thing isn't universal, but does require some safety training under a doctor's care to make sure that you're doing it right. Most folks don't require it at all.

0:33 Earwax 3:12 Baby teeth 5:40: crooked teeth 8:36 Appendix 11:22 🍑 14:10 👹🍑 15:44 Body odor 18:10 “Useless” structures (goosebumps, reflex pilomotor, tailbone, wisdom teeth) 21:26: nictating membrane 🤯🦅

My understanding of why humans still have body hair is to feel parasitic bugs crawling/landing on us before they are able to bite. Thus protecting us from diseases transmitted by them.

Whoever takes on the mission of studying butt hair.... I salute you! There should be a nobel prize just for doing this research xD

The answer to butt hair is #3 for chaffing. A process I have done is to shave only 1 side of the area at a given time, which removes excess hair from a single side with zero downsides, if done properly. The next time, (a week or so later), I shave the other side with the same results and keep the hair shorter and more manageable. If both get shaved at the same time there are many problems, mostly related to sweat as the skin cannot breathe. So, only clear one side at a time because you need SOME hair down there to counteract sweating, getting rashes, and chaffing.

"Even though its a cheeky question..." why is dad humor giving me so much joy these days?

When I got my permanent front tooth knocked out by a baseball, I grew another one! The dentist said I had another set and that it was a rare thing but there were more people with a third set than they realized. If it didn't happen to me, I wouldn't believe it either!

Hyraxes aren't rodents. They're actually relatives of elephants, dugongs and manatees. Weird, I know.

My second daughter had her wisdom teeth taken out and she had a teeny, tiny extra one in the roof of her mouth. So she actually had 5 wisdom teeth. I guess that made her smarter in the long run.

Q-tips are actually fine as long as you don't push into the ear canal. I use them to scrape lightly around the edges, putting a little pressure on to the canal as possible. You can still remove a decent amount of superfluous material without pushing it further in. The problem is, your instinct is to just drive it further in and start scraping, and most people don't even know where to stop in the first place. So really, it's better just to tell people don't do it at all. Massaging the space between your ear and your jaw/cheekbones and wiggling your jaw around can help break up a blockage. Holding your breath and blowing or sucking can also help to move material around and eventually drain into the sinuses. A warm moist rag over the ear may also be helpful. You can try using fluids. Warm water or even air can help somewhat, but can be unpleasant, and if you're careless, could be harmful to the ear drum. I've seen mixed opinions on hydrogen peroxide. On one hand, it's excellent at eating ear wax and can absolutely clear a blockage. On the other hand, it's highly corrossive, and will dissolve any biological matter it can. Giving that unfettered access to the inside of your face can be obviously problematic. I've seen first hand where a kid's eye started bleeding moments after recieving H202 through the ear. He turned out fine, but it was definitely a brick-shitting moment.

I love the appendix. I am a scrub nurse in the NHS in the UK. I first started in the 90s where appendicitis was a young person(4- 20) disease. Over the past 30 years it has moved through the generations and is now very common in the elder generation. I learned about the appendix upgrade from a vestigial organ to now, where it is thought to have a minor part in digestion. I suppose that the human body has to cope with our ever changing diet. I love the beauty op the human abdominal cavity. I has its own life. The colours are stunning. Yellows, pink, purple(ok so this is not something that any Surgeon would like to see). I find it amazing to actually see the peristaltic motion of piece of the small bowel. I actually recently saw Meckel’s Diverticulum, a first in 30 years of being a nurse. I’m still learning loads.

I grew a 3rd set of teeth, got around a dozen in a jar somewhere that i kept after the op. My mum said it was 'cos i was special, now i think i'm a freak. Cheers Scishow

Nice to see the legacy of litojonny :’) truly a legend

How nice would it have been if at like 40, we started to grow our 3rd set of teeth! Dentist would go out of business lol.

Ahhhh. My favourite form of entertainment....science and comedy. Thank you.

The appendix is basically an external hard drive and/or a system restart for your intestines. It stores a backup of the essential operating system and any major updates it may have learned. If your (intestinal) system gets wiped, the appendix can attempt to restore it to a previous functioning state.

Loved this video. For butt hair: we as human have (generally) hair around sensitive areas that we need to keep for reproduction, like genitals, or "body holes" that are susceptible/sensitive to environmental harm. For example head hair to avoid damage from sunlight incidence, nostrils hair to retain airborne pathogens and allergens, eyelashes for the same reasons and eye protection, hair in the ear canal or microvilli for protection as well as the same functions as nostrils, etc. Butt hair evolutionarily may have emerged for preventing small insects and other little animals to get into our body (as we were not wearing clothes/underwear thousands of years ago). Many insects and small coprophages are attracted to 💩 and humidity, so the hair can get them entangled and prevent them to keep going in ;)

I love my wisdom teeth! When I was around 9 I had to remove four of my molars due to them lacking enamel. Instead of having a gap, my wisdom teeth filled it and I now have a full set of functional teeth! :D I see the wisdom teeth as a small backup.

Everyone knows that you're not supposed to clean your ears with q-tips, but everyone does it anyway because it feels so freaking good! Normal people won't understand this, but those of us who have been to prison and had to wait weeks and weeks and weeks to get money on your account just so you can buy some coffee and q-tips.... You learn to appreciate those little cottony buggers...

You forgot to add sharks have rows and rows of teeth which break off when attacking prey. They keep sliding up row after row to replace them for future captures of prey.

Intergluteal cleft is a sufficient replacement for coin slot

17:30 I run a lot (10ks, marathons, ultras). If I shave down under, the chaffing gets much worse. So I don't shave. I can trim though, but not that much. In addition, if I'll run above 1 hour, I need vaseline, and tight fitting shorts. Yes, evolution made us into long distance runners, but only for the most motivated hunters: "to chafe or to starve, that is the question"

I was literally bored at work today and the question “why do we have butts” popped into my head. I opened my UKposts and this was in my recommended…

Again SciShow crew, add the word "Compilation" in front of these combo videos from the past!

Watching Hank age gracefully is one of the joys of scishow.

I have dry flakey earwax and I’ve always been very confused why people were grossed out by earwax, or had body odor. At least until i learned about earwax types

Fun fact: Wisdom teeth are normally not pulled in a lot of countries. A dentist will pick a rear molar that's the most worn and pull those teeth instead. That allows the wisdom teeth to naturally come forward and the patient has new rear molars :) and the process is way less painful compared to getting impacted wisdom teeth cut out of your jaw. Unless the wisdom teeth are so impacted that they are cracked, there's really no reason to get them pulled. I had to threaten to report a US dentist to get him to pull 2 rear molars with failing fillings instead of cutting wisdom teeth out of my jaw. Those wisdom teeth came in beautifully after about a year.

I would guess that butt crack hair as well as axilla hair also help suppress the creation of anaerobic environments in body folds by allowing air in between the strands of hair. Anyone who has ever worked around inactive and morbidly obese people can tell you just how much fun those folds can be when they cook long enough without any air circulation.

"Big butts are uniquely human" Me who has no butt: I guess I'm an alien 👽

What I can share about butthair is that it makes farting much louder if you dont have. Like when you blow some air by pushing your mouth into your arm vs. into a hairy head... So maybe it was a silencer :D

I went to my university’s student health in a panic one day because I suddenly couldn’t hear out of my right ear. It was just earwax! I was so embarrassed, but the nurse who flushed my ear told me it was super common.

If you do a lot of bending and lifting and a lot of stabilising hefty, awkward objects you rapidly learn a major function of your gluteus maximus. The amount of strain that it supports when your legs aren't completely straightened is significant.

I’m fortunate to have enough room in my mouth for my wisdom teeth. I’m also fortunate to still have my appendix.

So I'm watching this and keep getting dejavù listening to this guy. I finally figured it out, he does crash course on you tube. I watched all of his videos while I was in nursing school. Helped me understand what I was learning the most! Love hank!

I havent really watched this show in years but coming back to it feels like old times. You guys are the best at what you do, love it!

My appendix was my friend, then it tried to kill me. I broke up with it. Then I got a stomach ulcer from that one namey thing you mentioned... Ah, life. What a ride.

0:29 earwax 2:57 baby teeth 5:40 crooked teeth 8:35 appendix 11:20 butts 14:10 butt hair 18:10 vestigial structures

On the subject of wisdom teeth and jaw size: I have always speculated that the my family’s larger jaw size may have something to do with our diet. I grew up on a cattle ranch in Montana in the Eighties and Nineties, and let me tell you there were some lean years. We grew our own vegetables and ate the cattle that were too injured to save. There were some REALLY good steaks, and also some incredibly tough ones. The veggies were sometimes terrific, sometimes stunted and woody. I recall a number of times that I paused eating, not because I wasn’t hungry , but because my jaw was too tired to continue chewing. Our family dentist insisted on pulling my lower wisdom teeth as soon as they crowned around age 19. (Like my father, I never developed upper wisdom teeth or adult eye teeth). Now, I occasionally cut up my lower gums because of the lack of matching molars. I have to chew with an underbite to match molars in the back of my mouth. On a side note, I still resent my dentist for insisting on pulling my oversized baby eye teeth so he could replace them with virtually identical implants. I have to floss after every meal to remove the food particles that accumulate under the implant caps.

Speaking of butts and chasing down prey to exhaustion, I saw an Australian documentary on feral cats and the Aborigines that decided to make them food. I was impressed by this rather hefty woman chasing a feral cat, then finally walking over to it and just picking the exhausted thing up. This is now how I catch my dogs when they're avoiding their bath.

I'm definitely a very mature adult as I giggled every time "butt hair" was mentioned

When I was 14 I had my tonsils removed due to a investigation why I had an immune response resulting in a "cold" inflammation in my joints. I had in that time mild throat inflammation in my throat and they've said my tonsils must go because they might be the underlying cause of the whole thing. Years later they have discovered I have an autoimmune disease called Bechterew (aka Ankylosing Spondylitis) doe to a antibody called HLA-B27. Since then I am much more susceptive to viral or bacterial infections because my first line of defence in my throat has been removed. Removing the tonsils is still a very common practice where I am from (Hungary). I am worried that many more young people will suffer the consequences in later life without knowing how vital this organ is or was to them. I am now 44 and need to keep a close eye on what I eat or think twice if I washed my hands before taking any food because the very next thing I notice is having a diarrhoea or runny nose. My defence has been compromised by well educated doctors believing this organ can be removed without a price to pay.

My heart beats for you every day. I am inspired by you every minute, and I worry about you every second. It is wonderful to have you in my life.

On butt hair: As someone who once shaved my butt hair, I have experience as to the differences between having and not having it. One reason is that it prevents small chunks from getting too far if you fart. The other, and the main reason I stopped shaving, is that the hair traps sweat. If you don't have it the sweat runs down your legs which is super gross and annoying. It's also a pain if you don't keep it shaved due to chafing. The reason I started shaving it was curiosity and I noticed it did make it far easier to clean after pooping.

So my obsessive gum chewing as a kid is the reason why all my wisdom teeth grew in without impacting? Sweet!

Here’s a question: if everyone had a unique scent based on their microbiomes and stuff, does that mean identical twins will smell the same too, or are the microbiomes more responsible for the smell, which I assume could develop differently in twins considering it’s more about what kinds of bacteria are favored because of their diets?

These intellectual people have so many interesting matters to discuss, I never thought I needed answer to all of these questions...you guys have gained a humble subscriber, well done and thanks!

I had a pilonidal cyst while I was in the army, being a typical soldier I didn’t want to go to sick call, be told it was nothing, and then be accused of “shamming” when I got back to the unit with a “return to duty” sick slip. But it was a bump right at the top of my butt crack, a little to the right, and it *ITCHED* when I had to sit for long times (driving in convoys, classes, etc.) I’d press on it and a watery pinkish fluid would come out, though when it itched it was more opaque and yellowish. It never once hurt. Anyway, this went on for a year or 2, until one night we were on the way back from the rifle range and I was sitting on the wooden troop seat in a 2 1/2 ton truck. My cyst itched like never before, and it was pure murder having to sit around cleaning weapons, turn them in, and wait for everyone to get done. Finally everything was clean, we had formation, and were released. I went right to my room to take a shower before bed, but first I started pressing and poking at the cyst. Foot on the toilet seat, bent forward, standing straight, leaning to one side or the other, trying every position I could think of to press from a different angle. All of a sudden I felt a POP, a flow, and sweet relief. In my hand was what I assume was a mix of hair, blood, dead skin cells, sebum, dirt, etc. It was a couple inches long and actually looked a little like an earthworm. This was about 25 years ago and it’s never come back. I still have a dimple where it was, though. Watching Dr. Pimple Popper has told me the sac was still in there but it’s never grown back.

I regret shaving my butt hair when I was a teen. Those newly growing butt hair were prickly as all hell!

Earwax makes sense. Wisdom teeth make sense. Ass hair doesn’t make sense.

I'm a professional soccer referee, which means I run an average of 200 miles a week as part of my job. I started shaving my butt and legs about 2 years ago, and have noticed no changes to chafing around the cheeks, but there was definitely an increase in thigh chafing.

😂 I don’t have ad-free UKposts but it’s turned out to be hilarious sometimes. I just experienced one of the best ever! Show host says: “I wanna talk a little bit about butts, because -“ Buick ad interrupts: “That’s a really tight spot…” Me: 💀

My 24 year old daughter, born in 1998 has no wisdom teeth! I was so jealous! I had to have all 4 of mine removed! This was such neat information! Thank you!

Species like beavers and groundhogs constantly grow teeth.

Fascinating and delivered in a very amusing way. As always. Thank you!

Years fly by, but the heart stays in the same place.

It’s obvious that the reason we have butt cheeks is to provide an audible biohazard alarm.

Funny thing: my teeth are too small for my jaw and are crooked because of having too much space 🤷🏻‍♀️

13:15 vid: "humans are the only primates who can run long distance" me who always sit: 😮

The host summer was too short every second deserves to be loved.

What length of fingernails is actually usefull and when does it get cosmetic?

I think reducing chafing is the most likely answer for butt hair. Keep in mind that chafing can also occur when wiping, which historically might've been done with less soft objects such as wood, rocks, and shells.

I might have seen this before, or I might have seen most of the older videos featured in this compilation. Regardless, this was perfect to listen to and intermittently watch while I did a couple of tedious chores. I love this channel.

I was really lucky to have naturally straight teeth. All my highschool friends had to get braces, and some people didn't believe me when I told then I never had braces myself. But, y'know, I'm one of the many people who needed to have their wisdom teeth removed. Something seemingly went wrong during the healing process and it had my gums recede in the far bottom left corner of my mouth, which exposed a hole below my last molar. I had my wisdom teeth removed in 2008 at age 18 - I had to get several fillings on that molar because of food getting stuck in that exposed gap, until I had to get root canal surgery. Worst dental experience EVER. But it didn't end there. The pain persisted because root canal surgery doesn't actually kill sensation to the tooth. In 2016, the tooth broke while I was eating (eating RICE, of all things). I had to go and get it repaired, which was expensive, and they put a crown on it. Lost the crown. Tooth broke again. They put another crown. It didn't help. By 2020 or something, I had had enough. I went to the dentist and told them to pull the tooh. They still tried to convince me to get another crown, but I knew they just wanted my money, so I put my foot down and said NO. Pull the goddamn tooth. From getting my wisdom teeth removed at age 18, I'm now 32 and have 31 teeth. The pain is gone and the rest of my teeth have fortunately shown no sign of shifting. tl;dr Teeth are frickin' weird but please take care of them, and make sure to find reputable and trustworthy dental professionals.

SciShow knew we’ve all had that question about butt hair…

11:57 gives new meaning to the phrase smart ass

18:13 So cool of them to let Hank's little brother do the last segment!

If you keep a good track of what your ear wax is doing and you insert the q tip without pushing Then you can gently twist it around and scrape off ear wax around it and then pull it out without ever pushing it back in. that's not impossible to do. It's not only messy, but it will get on anything that you use around your ears, like headphones.

I can just imagine the ancient, pre modern man pick up lines: "damn girl! You hunt with that ass?!" 😆

I've once shaved my Butt Hair and I can vouch for reason no.3. It does help to reduce friction and rashes when you walk, especially in summer when you sweat a lot. NEVER EVER GONNA SHAVE MY BUTT HAIR. THEY ARE PRECIOUS

Butts also help protect and support the pelvic bone when sitting. As someone with an extremely flat but I actually experience pain when sitting in chairs that don’t provide support for any amount of time. It’s a real problem for me.

Love is not only rich and colorful, but also good to hear or see.

Video: You don't see other species and go 'gee that beaver's teeth should be straighter...' Me, an animal science student: Gets flashbacks to the dentistry unit of horse class, in which we learned that horse braces are in fact a thing that exists...

11:34 Why would evolution grant us such an ASSet. 😃😃

My favourite vestigial structure is not in humans, but in snakes! My pet ball python still has vestigial legs, and I think that's so cool!

"You're a really good actor absolutely love old-school Hanks narration 👌❤️ also personally got wisdom teeth, but I also got hella lucky, as they sitting vertically inside my lower jawbone & skull. They're not going anywhere. Although, since I'm missing 4 of my adult teeth (thanks Klinefelters), I could probably use them.

Just a detail i wanna clarify here (Because creationists love to misrepresent it) Vestigial means that a structure has lost its original purpose. It does not, however, mean that the structure is useless. Things like the appendix fulfill a purpose, just no longer their original ones.

2:52 Stopped using cotton swabs, after realizing a Phillips screwdriver works better to get rid of the itch. These days I use ear spoons out of surgical steel. ... Either those or banging my head against the next concrete wall till I -loose conscious.- Edit: lose consciousness. I shouldn't be posting in a foreign language half asleep from a mobile device. It always ends badly grammar wise. @Matt thanks for the correction.

this adventure into my bodys strange things was fun . I learnt a lot. thanks.

Hi everyone, concerning the "Butt Hair", from my own experience, after having undergone several chemotherapy treatments and like most of the people who have experienced this, I lost all the hair on my body...when I started to walk again and before all the hair grew everywhere, I had irritations in the parts that are not exposed to the sun and where the skin rubbed agains skin (I needed to use some medical cream)... so in my opinion: theory nb.3 is the right answer

I've learned so much from Hank Green and crew over the years. I'd proffer one small correction: nic·ti·tat·ing membrane instead of nic·tat·ing.

"A toddler's jaws are tiny, and could never fit in a full set of 32 adult teeth, because that would be super horrible and terrifying and no one would get anywhere near them." :: Gary Busey has entered the chat. ::

About the earwax problem: I have used the "q-tip" method my whole life and never had a problem with it. My mother and wife OTOH used the flushing bladder with liquid or went to the doctor to fix thr problem. Both of these methods ended in fiasco, with the situation worse. Of course eventually it was (sometimes partly) fixed, but not without pain and time. As I said I have never had a problem, maybe a clogged ear 2 - 3 times in my life. Now I don't do this often maybe one time a week or more often less than that. Btw, I never push the earwax IN, I position the tip max in without touching the sides of the earcanal and then "scrape" the sides of the canal in a spiral movement out.

Equally informative and entertaining. Nice balance.