Have you ever noticed that different people have different scents? Go on, sniff your friend, we’ll wait. Today’s episode dives nose-first into what makes up our personal scents. With the help of Candace, a one-of-a-kind candle maker interested in making podcast-scented candles, we get the lowdown on body odor. We’ll also hear about super-sniffing animals and some other creatures that thrive on stink. And there’s a new Mystery Sound -- this one is definitely not a stinker!

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KID SPEAKER 1: You're listening to Brains On!, where we're serious about being curious.

KID SPEAKER 2: Brains On! is supported in part by a grant from the National Science Foundation.


CANDICE: Are you tired of boring, old, pleasantly scented candles?


Flowers, fresh linen, vanilla-- what a snooze for your schnoz!


Why not take your nose on an adventure? You need a unique smell experience tailored to what your nose wants. [EXHALES] Hi. I'm Candice of Candice's Candle Emporium. [DOORBELL RINGS] Come on down to my one-of-a-kind workshop and I'll whip up a custom candle for any scent you could possibly imagine.

MAN SPEAKER 1: Hmm-mm.

CANDICE: That new-book-from-the-library smell? [INHALES THEN EXHALES] Paper, a hint of glue, and just a whiff of that mustard stain on page 24?


Your favorite superhero action figure that's been in a box in the basement? [INHALES THEN EXHALES] Plus sticks-- sticky cherry popsicle residue and just a smidge of mildew.


Hmm, ever smelled shark breath? [WATER SWOOSHES] I bet you haven't, and I bet you are curious. Who needs the smell of cinnamon buns when you could have the smell of cinnamon Bunny-- [BOING] your favorite pet rabbit. Stay tuned for my newest line of spectacular nose ventures, The Podcast Collection. Light one of my candles when you're listening to your favorite pod, and it'll smell like the hosts are right there in the room with you. So get your nose and ears ready. [EXHALES]


MOLLY BLOOM: You're listening to Brains On! From APM Studios. I'm Molly Bloom, and my co-host today is Scarlett from Topeka, Kansas. Hi, Scarlett.


MOLLY BLOOM: OK, Scarlett, I need you to stop what you're doing and take a big sniff. [SNIFFS] What do you smell? Maybe some food cooking or your parents' coffee or maybe you're in a car and you smell exhaust or an air freshener?

SCARLETT: I smell microphones. They smell microphone-y.

MOLLY BLOOM: [CHUCKLES] One thing you're probably not noticing is your own smell. But it's always there, and it's unique to you, like a fingerprint-- or a stinker print.


Today we're talking personal sense and answering a question you had Scarlett.

SCARLETT: Why do all people have different smells?

MOLLY BLOOM: So Scarlett, what made you think of this question?

SCARLETT: I just noticed that my mom and dad smells kind of different.

MOLLY BLOOM: How would you describe their smells?

SCARLETT: I don't really know.

MOLLY BLOOM: Do you think you have a scent?

SCARLETT: Probably. I think everybody probably has one.

MOLLY BLOOM: Mm-hmm. So if you could choose your body scent to smell like anything, what would you want to smell like?

SCARLETT: Probably just tropical fruits, like pineapples and mangoes.

MOLLY BLOOM: Oof. I love those smells. That would be delightful. Are there any smells you absolutely can not stand?

SCARLETT: Probably nail polish remover.

MOLLY BLOOM: Ooh, yeah. That is a strong, strong smell. So are there other people in your life that you've noticed, besides your parents, that have distinct smells?

SCARLETT: I just noticed that other people's houses smell different, kinda.

MOLLY BLOOM: Hmm. Like when I go to my grandma's house, there's a very specific smell, and I love it.


MOLLY BLOOM: It smells like her perfume and, I guess, by just her, and I love that smell. Are there like friends' houses that you like know the smell of that you could describe the smell of their house?

SCARLETT: Probably my aunt's house.

MOLLY BLOOM: And what would you say her house smells like?

SCARLETT: Probably like fancy candles and perfumes, [CHUCKLES] a lot of essential oils. She has a dog too, and it's favorite food is sheep puree.

MOLLY BLOOM: Sheep puree?



Kind of disturbing. And they have a sheep fur on their chair, so very disturbing.

MOLLY BLOOM: That's a lot of different smells. [LAUGHS] So you got the oils, you got the sheep puree and sheep fur and the dog. Wow. That must be a lot for your nose to process when you walk in there.

CANDICE: [EXHALES] The sweet smell of B.O. No way! I showered today.


CANDICE: No, no, no, no. Brains On! Headquarters-- B-Oh, not body odor B.O.


MOLLY BLOOM: Uh, yeah.

SCARLETT: Wait, you're Candice.


SCARLETT: I love your Taco Tuesday scented candles.

CANDICE: Well, you're in luck. I'm here to capture the magnificence of Molly, Marc, and Sanden for my new podcast candle collection.

MARC SANCHEZ: Did somebody say "magnificent"?

SANDEN TOTTEN: Yeah-he-he. We topped the charts, everyone.

CANDICE: [SNIFFS] Mm, Sanden, you smell like a true podcaster-- a bit minty, notes of headphones and cables, with a bright note of brains.


CANDICE: And you, Marc, [SNIFFS] mm, I'm getting a strong essence of curiosity, with a touch of razzle dazzle.

MARC SANCHEZ: Ha! Cha-cha-cha-cha-cha.

CANDICE: Molly is [SNIFFS] hostess with the mostest, like the cupcakes-- sweet and ever delightful with a pinch of cinnamon for sass.

MOLLY BLOOM: Oh, thanks.

CANDICE: Time to collect your scents. I just need to find my wiffer-sniffer. Hmm, where is it? Oh, here it is. It's like an electric toothbrush with a nose hose that ends in a whirring, furry puffball. Let's sniff up some smells.

SANDEN TOTTEN: What in the--

CANDICE: Don't worry. It doesn't hurt. Let's start with a skin scan. You see, everyone is born with a unique scent. It's called your odor type. It's detectable in body fluids, like your sweat and your spit.

MOLLY BLOOM: [GIGGLES] That tickles.

CANDICE: Sorry. Got to get in your armpits. I need both types of sweat.

SCARLETT: There are two kinds?

CANDICE: Yes. You have millions of sweat glands in your body, and most of them are eccrine glands. These little guys are found all over your body, and they secrete sweat-- that's 99% water to help keep you cool.

SCARLETT: Like your own personal air conditioning.

CANDICE: Exactly. There is another type of gland called the apocrine gland. These glands are found in your armpits and scalp, and they secrete a thicker, more oily sweat. Bacteria on your skin eat that sweat and burp out smell-filled chemicals.


Those chemicals create a terrific, specific aroma.


CANDICE: Yes. Getting a marvelous sample of some B.O.B.O. Right now-- all thanks to Molly's armpit bacteria.

SCARLETT: Molly's armpits have bacteria?

CANDICE: Oh, yes, tons. We all do. These helpful, little bacteria are part of your microbiome. Your microbiome is made up of all the microorganisms living in and on your body. They are a big part of what makes you smell like you. Your sweat and the oil on your skin are odorless until the bacteria swoop in, gobble it up, spew out chemicals, and contribute to your signature scent.

SANDEN TOTTEN: Uh, excuse me, Candice, is it my turn yet? I've got to go soon and--

CANDICE: Don't stress, Sanden. It changes the way you smell, and I don't want your listeners associating you with stress. There is ample research suggesting that humans can smell certain emotions, like stress and fear.


CANDICE: When you're anxious or afraid, your body enters fight-or-flight mode, and cortisol, the stress hormone, enters your bloodstream. This activates your apocrine glands, you sweat, and your armpit bacteria generates a big stink.

SANDEN TOTTEN: [SNIFFS] Uh-oh, I can feel the big stink coming on.

CANDICE: And your fear can also be contagious. Scientists have found that when someone else gets a whiff of your fear sweat, it can increase their heart rate and blood pressure. So they feel like they're afraid too even though they don't know why.


CANDICE: It is cool. But you don't have to worry about this, Scarlett. Not yet. Apocrine glands aren't activated until you go through puberty. That's when your body starts changing from a kid into an adult. So, kids, don't get B.O.

SCARLETT: Phew! That's a relief.

CANDICE: You are not too stressed today, Molly. Very nice. Now, open wide. I need some Molly mouth scents.


CANDICE: Hmm, I'm getting a hint of garlic, a touch of honey, and behind it all, a perfect scent of Molly mouth.

SCARLETT: We have unique breath sense too? I mean, besides good breath and bad breath?

CANDICE: Yes. Everyone has their own signature saliva in different amounts and types of bacteria in their mouth. But, of course, what you eat and how well you clean your teeth impacts how it smells. Molly, you've got great oral hygiene habits.


CANDICE: That garlic is pesky, though. Its scent lingers. The smell of garlic even comes out of your pores-- those tiny holes on your face that you can see if you look really closely. Hmmph, I'm surprised I didn't notice it more during your skin scan.

MOLLY BLOOM: I'm glad you didn't.

CANDICE: I was probably too distracted by the ways your environment has impacted your scent. In addition to your genetic odor type, hygiene, and diet, your environment, or the stuff in the world around you, influences your personal scent.

MARC SANCHEZ: Oh, wait, wait, wait. People can smell that I'm from California?

CANDICE: Not quite, Marc. But they might be able to smell that you had a smoky cookout in your backyard last night.

MOLLY BLOOM: What are some of the environmental smells you picked up on me?

CANDICE: [SNIFFS THEN EXHALES] The brisk and brilliant notes of Brains On! headquarters-- lemony fresh with a hint of sound waves and sparkles. Marc, you're next.

MARC SANCHEZ: All right, let's do this. I'm going to buy Marc-scented candles for everyone I know. That's my mail carrier, my personal trainer, Molly, my dog.

MOLLY BLOOM: OK, come on, Scarlett. Let's let these guys finish their wiffer-sniffering in peace.

MALE SINGERS: (SINGING) Ba-ba ba-ba, ba-ba ba-ba, ba-ba-ba, Brains On!

MOLLY BLOOM: Let's give our schnozes a rest and focus on our noses of noise.

SCARLETT: Our ears?

MOLLY BLOOM: Exactly. Hit it!


KID SPEAKER 3: (WHISPERING) Mystery sound.

MOLLY BLOOM: Here it is.


OK, what is your guess?

SCARLETT: Sounds like dribbling or maybe like basketball shoes like running.

MOLLY BLOOM: Mm-hmm. That's a great guess. Yes, very rhythmic.

SCARLETT: Like a pattern.

MOLLY BLOOM: Yeah, like a pattern. We'll be back with the answer and give you one more chance to guess right after the credits. Stay tuned.


We're working on an episode about our remarkable imaginations, and we want to hear from you. If you've had an imaginary friend now or in the past, we'd love to hear about them. Scarlett, I'm wondering, have you ever had an imaginary friend?

SCARLETT: My mom says that I used to have one when I was like a three-year-old, and I used to call her the "bowling lady" and like give her my toys and stuff.



MOLLY BLOOM: I love Mrs. Bowling. I'm so curious about her-- if she just like really liked bowling or if that was her last name. [LAUGHS]

SCARLETT: My mom said when I went to my Nana's house, my Nana's room would be like her fortress. And I'd tell my Nana, don't go in there. The bowling lady is in there.


And I was like bringing her my toys and stuff.

MOLLY BLOOM: I love that. That's so cool. Our imaginations are wonderful things.


SCARLETT: Sometimes.

MOLLY BLOOM: Sometimes

SCARLETT: Unless you have a nightmare, it's--

MOLLY BLOOM: [CHUCKLES] Oh, yeah, natural--

SCARLETT: Imaginary friend like me.


SCARLETT: I would give her my toys and stuff, and my mom said I even had nightmares about her sometimes.

MOLLY BLOOM: Oh, no! So the bowling lady was a little scary.


MOLLY BLOOM: Oh, no. [CHUCKLES] Well, listeners, please record yourself telling us about your imaginary friend and send it to us at brainson.org/contact. And while you're there, you can send us mystery sounds, drawings, and questions.

SCARLETT: Like this one.

KID LISTENER 1: Hi. My name is AJ, and I'm from San Diego. My question is, are mangoes really related to poison ivy?

MOLLY BLOOM: Again, that's brainson.org/contact.

SCARLETT: And keep listening.


KID LISTENER 2: If I could smell like anything, I would smell like honeysuckle.

KID LISTENER 3: And if I could smell like anything, I'd smell like theater.

KID LISTENER 4: If I could smell like anything, I would smell like doughnuts because they're tasty and I love doughnuts.

KID LISTENER 5: I like to smell like fresh croissants and a field of roses.

KID LISTENER 6: If I could smell like any scent, it would be a rose. Another family member agrees. We both like the smell of roses.

KID LISTENER 7: If I could smell like anything, I would smell like lavenders because they smell really nice.

KID LISTENER 8: I would smell like cinnamon buns because they taste pretty good.

KID LISTENER 9: My favorite smell is my mom, and my preferred smell is probably cake.

SCARLETT: You're listening to Brains On! I'm Scarlett.

MOLLY BLOOM: And I'm Molly. Wow. Those were some sweet-smelling answers that our listeners sent in. Thanks to Annie, Layla, Cormack, Riley, Sydney, Cathy, Lulu, and Shree for sending those in.

[INHALES THEN EXHALES] So we all have special scents that come from our genetics, our sweat and bacteria, what we eat, and even the places we go. But there are other smells we give off too, like when we're sick. These smells are too weak for our noses but not for one group of super-smellers.


That's right-- dogs.

SCARLETT: Dogs can be trained to sniff out certain diseases, like cancer, diabetes, or possibly even COVID-19.

MOLLY BLOOM: It all has to do with their super-sensitive, ultra-efficient, colossally cute noses. How sensitive are they? OK, picture a barrel of apples. [POP] Now, imagine there's a stinky, rotten apple in the barrel. [WOODWIND SOUND]

GIRL 1: Eww.

MOLLY BLOOM: You might be able to catch a whiff of that rotten one-- but probably not. A dog totally could. OK, now picture two million barrels of apples.


And again, only one rotten apple.



There's no way you'd be able to smell it, but a dog totally could.


SCARLETT: Some diseases give off smells too. And with training, studies show dogs can pick up these scents as good as, or even better than, lab tests.

MOLLY BLOOM: But as cool as it would be to have doctor dogs at hospitals, it's actually really hard to train them, and we don't always know what they're trying to tell us.


Is someone's sick, girl?

[SMALL DOG BARKS] Did someone fall down the well?


Oh, a squirrel looked at you?


Mm, OK.

SCARLETT: So scientists at MIT are working on a smelling machine that can also detect disease smells. It's like an artificial dog's nose.

MOLLY BLOOM: No way it would be as cute, though.

SCARLETT: Definitely not.


KID SINGER: (SINGING SLOWLY) Brains On-- don, don.


SCARLETT: Did you hear that?

MOLLY BLOOM: Hear what?


SCARLETT: That voice. It sounds like it's coming from over here.

MOLLY BLOOM: It's a fly on the wall.

FLY ON THE WALL: Ha! Finally! I've been buzzing around Brains On! headquarters for three seasons now, and I just can't hold my tongue anymore. You humans are always trying to cover up your natural funk. I've seen Rosie offering up samples of her fancy New York City Orange Patchouli Hand Cream. And Marc? Always reapplying deodorant after things get even the slightest bit tense during an experiment. What a waste!

MOLLY BLOOM: [SNIFFLES] I'm sorry to interrupt, but did someone forget to take out the trash? Something reeks.

FLY ON THE WALL: That is our first guest. In order to encourage your listeners to savor the stink, I've invited some expert guests from around the animal kingdom to make their case. Give it up for Tammy the Tamandua. She came all the way from South America, so please--


Mind your manners.

SCARLETT: How can an animal so cute be so stinky?

MOLLY BLOOM: Yeah, she looks just like a small anteater. She's got big, clumsy paws, a cute, little snout, and fur that looks so soft to touch. [SNIFFLES] But, [SNIFFLES] god, I can't bear to get any closer.

SCARLETT: I'm just going to take a step back over by the window. No offense, Tammy.

TAMMY THE TAMANDUA: None taken. In fact, that's the whole point. What you're smelling right now is sort of my resting odor-- stings your nostrils just enough to keep you from getting too close. As you can see, I'm much smaller than my better known cousin, the giant anteater. I'm snack-sized, some might say.

So if you were a pair of, say, hungry jaguars, you might shrug off my signature scent and try to keep approaching. [CHUCKLES] Bad idea. If a predator comes too close, they're going to get a schnoz full of stink. My spray is four times as potent as a common skunk's.

MOLLY BLOOM: That does seem like a good way to scare off hungry jaguars.

FLY ON THE WALL: Pretty stellar, right? Next up, it's Kevin the dog. What's up, my pup? Give me the news from the neighborhood.

KEVIN THE DOG: Whew! Big day. Huge day.


Lucy, the poodle from next door, was in a bad mood. I think it was because she ate some stale cereal that the baby probably dropped. She's got a sensitive stomach. I also ran into Frankie, the little wiener dog who lives around the corner. He was all jazzed because he'd just come back from an off-leash hike in the woods.

MOLLY BLOOM: Wow, Kevin. You're really in the know. How did you find all this out?

KEVIN THE DOG: Butt-sniffing, of course.


We dogs secrete chemicals called pheromones that communicate all kinds of important information-- mood, diet, health. We can also smell where other dogs have been recently. It's like being able to sniff your friends' social media updates.

SCARLETT: So dogs are making pheromones all the time?

KEVIN THE DOG: Yeah. We have two sets of glands that release these chemicals-- one by our ears and the other by our butts. It's rude to approach a new dog head-on, though. So to be polite, we always make a beeline for the back side.

QUEEN EILEEN THE HONEYBEE: Did someone say beelines? I've been practicing mine.

FLY ON THE WALL: [GASPS] Your Majesty! What an honor to have you on the show. Everyone, this is Queen Eileen, [TRUMPET SOUND] the honeybee. Now, tell me, you also release pheromones. Is that right, Your Majesty?

QUEEN EILEEN THE HONEYBEE: But of course! The queen mandibular pheromone that I release is paramount to maintaining order in the hive. Think of it like my own personal announcement system. It lets my loyal subjects know how I'm doing-- the smellier, the better, of course-- and alert them when I need them to take care of me. It even communicates to the worker bees not to raise any more queens. That would cause quite a swarm.

FLY ON THE WALL: Thank you, Your Highness.

SCARLETT: Long live Queen Eileen! [TRUMPET SOUND]

FLY ON THE WALL: So you see, stink is a superpower. Down with deodorant! Free, love, funk!


SCARLETT: You know, those stinky animals made some good points. Smells can be pretty powerful. [COUGHS]


MOLLY BLOOM: Yeah. I'll say even our best air freshener is no match for their scents. But I know what you mean. It makes me kind of sad that we can't do as much with our odors as animals can. But did you know that baby humans rely on smell a lot?


MOLLY BLOOM: Yeah. When babies are just born, they can't really see.


But they seem to recognize family members by their smells, so they know who to trust.

SCARLETT: That's pretty cool.

MOLLY BLOOM: And there's some research that suggest smell might be part of how we choose a romantic partner. [HARP SOUND] We might not think about it but we may like the smell of people who would make a good partner for us. In fact, some scientists think we might use smell in a lot more ways than we know. Like it's just something guiding us in the background. But there's still a lot to learn.


Is that better?

SCARLETT: Still stinks like Tammy in here.

MOLLY BLOOM: Maybe we should light one of those candles Candice left us.

SCARLETT: Do you want the Scent of Water From a Hose on a Summer Day or the smell of Getting a B-plus on a Math Test?


CROWD: Brains On!

CANDICE: Podcasts, they're not just for your ears anymore. New from Candice's Candle Emporium, it's the Scent of Pod series. [INHALES] These singular scents directly from the source pair perfectly with the mellow tones of your favorite hosts.

The Brains On! candle perfectly captures the essence of Molly, Marc, and Sanden, with additional notes of library book, zesty lime, and [ICE CLNKING] just a whisper of Gungador musk.


CANDICE: And explore the sense of history with the Forever Ago candle. For just five easy payments of $9.99, you'll smell ambergris ice cream, salty ocean air, Joy Dolo's favorite socks, and delicate notes of museum hallway. This Smash Boom Best set comes with two pairs of competing scents-- Sundaes Versus Nachos, Sneakers Versus Jeans-- light them up and see who burns the brightest.

So buy now and enjoy the smell of podcasts-- or, as I call it, "poddy" odor.

MOLLY BLOOM: There are lots of things that affect the way we smell. Our DNA, our diet, our health, and the bacteria living on and inside our bodies all play a part.

SCARLETT: Emotions, like stress or fear, can affect our smell too.

MOLLY BLOOM: While we humans sometimes use deodorant or perfume to mask our natural musk, other animals really bring the funk.

SCARLETT: They might use scents to mark their territory, to identify friends or family, or even as a defense against predators.

MOLLY BLOOM: Smell can communicate a lot of information to animals with more sensitive noses. Dogs can even be trained to sniff out certain illnesses.

SCARLETT: And while we humans don't use our sniffers quite so much, there's evidence that human babies depend on smell to identify their parents and other close family members.

MOLLY BLOOM: That's it for this episode of Brains On!

SCARLETT: The episode was produced by Molly Bloom, Rosie DuPont, Anna Goldfield, Rubie Guthrie, Marc Sanchez, Anna Weggel, and Nico Gonzalez Wisler.

MOLLY BLOOM: Our editors are Sanden Totten and Shahla Farzan. This episode was sound designed by Rosie DuPont and mixed by Anne Haberman. We had engineering help from Jess Berg and Steve Kincaid and a special thanks to Kelsey Wishman. Our executive producer is Beth Pearlman, and the executives-in-charge of APM Studio are Chandra Kavati, Joanne Griffith, and Alex Shafford.

SCARLETT: Brains On! is a nonprofit public media program.

MOLLY BLOOM: And if you can't get enough of the show, head to brainson.org. You can listen to past episodes, donate, get your very own Brains On! baseball cap, and submit questions for future shows. All right, Scarlett, it's time to listen to that mystery sound one more time.


All right, have you any new thoughts?

SCARLETT: I still think it just sounds like dribbling on a basketball court or like running.

MOLLY BLOOM: Mm-hmm. I think jump rope. That's my guess.

SCARLETT: Ooh, yeah. Oof. I kind of wish I could put your guess with mine. [CHUCKLES]

MOLLY BLOOM: I mean, you can change. We can both be jump ropers.

SCARLETT: I'm being-- I think I'm something.

MOLLY BLOOM: I think dribbling is good too.

SCARLETT: I think I'm sticking with dribbling. I'm sticking with dribbling.

MOLLY BLOOM: I love it. I love it. All right, let's hear the answer.

KID LISTENER 10: Hi. I'm Maggie from Middlefield, Ohio. And that was the sound of me jumping on my pogo stick.

MOLLY BLOOM: [GASPS] Pogo stick.

SCARLETT: I didn't even know they still have those.


SCARLETT: I thought they were all took down for scrappers.

MOLLY BLOOM: [LAUGHS] So you know what a pogo stick is?

SCARLETT: Yeah, I do. It's kind of like a bicycle with a bouncy thing at the bottom with no like-- and you just hold on to it.

MOLLY BLOOM: Yeah, there's no seat. It's kind of like a stick with like place for your feet to go so you like stand on it and kind of bounce around. Wow. Yeah, that's a tricky one, [LAUGHS] for sure. You heard it here first. Pogo sticks are making a comeback.



SCARLETT: Not right. Not the pogo sticks.




MOLLY BLOOM: Now it's time for the Brains' honor roll. These are the incredible kids who keep this show going with their questions, ideas, mystery sounds, drawings, and high fives.



We'll be back next week with more answers to your questions.

SCARLETT: Thanks for listening.

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