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Clinical Sexologist and Sexplanations Host Lindsey Doe teaches Hank the difference between HIV and AIDS. Then Chinchilla Ash teaches Hank about softness.

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[Intro music]

Hank Green: Hello and welcome to another episode of the SciShow talk show. Today we are joined by clinical sexologist and host of Sexplanations, Lindsey Doe! 

Lindsey Doe: Hi!

Hank: You know all about sex and anatomy and how life works.

Lindsey: Incorrect. I know some of a lot of it, but not all of it.

Hank: Ok.

Lindsey: I try though. And it's fascinating so I like studying it and learning more.

 Stump Hank

Hank: Ok. Do you think you have a way to, uh, to stump me?

Lindsey: I have a question that I ask my students at the university which I would love to run by you and see if you would miss a point or not on my exam.

Hank: [laughs] Ok.

Lindsey: Ok?

Hank: [laughs] That was... Ok.

Lindsey: Can someone contract AIDS from having sex one time with one person who is...who has AIDS?

Hank: Yeah.

Lindsey: Stumped!

Hank: What?

Lindsey: [laughs] You're stumped. Because you can't contract AIDS. You contract HIV, the virus.

Hank: Aaah. You trick-questioned me. 

Lindsey: So, in the time period that we have known about the virus, it has changed names a lot and it's also changed the number of stages and how we define those stages, AIDS being the final stage. So, if I have a type of virus that created the symptoms of puking and nausea and fever, chills, etc., and I sneezed on you, I'm not giving you puking.

Hank: Right.

Lindsey: I'm giving you whatever that virus is. So the same thing goes with HIV and AIDS. If I have AIDS and we were to engage in some sort of risk behavior, such as sharing injection drug...

Hank: [laughs] Sounds like fun!

Lindsey: ...paraphernalia, um, unprotected intercourse, or breastfeeding, or if we were to get in a car crash...

Hank: I will, I will do, I will make sure to not do any of those things with you.

Lindsey: Thank you. Um. Any, any sort of blood, seminal fluid, vaginal fluid, or breast milk exchange.

Hank: Uh huh.

Lindsey: Then I am not infecting you or putting you at risk for AIDS. I'm putting you at risk for HIV, and then whether or not that transforms into AIDS or manifests as AIDS, um, really depends on what you're exposed to and how the virus lives in your body.

Hank: Hmm. So HIV stands for...

Lindsey: Human Immunodeficiency Virus

Hank: And AIDS stands for...

Lindsey: Acquired Immunodeficiency Syndrome

Hank: So the syndrome is the set of symptoms, basically.

Lindsey: Correct.

Hank: Interesting. And we named it that because we weren't quite sure what the heck was going on when we first started to identify that.

Lindsey: Correct.

Hank: That was a terrifying time.

Lindsey: It was.

[both laugh]

Hank: Most people watching this probably won't remember that.

Lindsey: No. I am, uh, the same age as our knowing of the virus, but it is believed that it existed even prior to 1981 and it wasn't until we had, um, a somewhat homogeneous group being infected at the same time, with the same symptoms that we are able to go in and say, oh wow, maybe this isn't actually pneumonia, or tuberculosis, but maybe there is another cause that is creating what is now a pandemic.

Hank: So what, what is that process of going from being infected with the virus to, um, having AIDS?

Lindsey: All right. So, at the beginning, you have a point of infection, where the person has come in contact with the virus and if their body receives it, it will attack the immune system, which is the part that is actually designed to protect their body against viruses. So, when I teach people about HIV and I have my PowerPoint set up, there is a little virus, a sphere, with, um knobs on the end of it, and it has these arms that should be all muscular and wonderful, but they're actually saggy and droopy, because it's meant to demonstrate how weak this virus is. It really needs its host in order to survive. And it also has Einstein hair, so I made this squiggly gray mass above the sphere to talk about how intelligent this virus is, that it is going to attack the exact part of the body that is meant to fight it. So here in Missoula we have the Grizzlies, our main opponent is the Bobcats in Bozeman, and in this analogy it would be like, um, the Bobcats the virus coming over to our Grizzly quarterback, stripping it down, dressing it up in Bobcat, um, jockstrap, jersey, helmet, mouthguard and those bands that they wear on their wrists with the game plays. And then, now you have the Grizzly quarterback operating with the Bobcat agenda, so it's, it's a brilliant virus. All right. So now we've got point of infection, and then after this there is, um, a fair amount of time, sometimes even 20 years and beyond, that this person could be asymptomatic, where they're not expressing any symptoms, experiencing any symptoms for a very long time. So if they're not getting, um, any feedback from their body that something is wrong, they might not get tested and they might continue to infect other people, and then after that period, an AIDS diagnosis is made when there are 200 or less, um, what are called CD4 or T-cells in a microliter of collected fluid, and that's when your immune system, or the score of the Grizzlies, has completely dropped at that point. Or, if they have been, um, if they have acquired a disease that the person otherwise wouldn't get if they were healthy.

Hank: So there, there are 2, 2 criteria...

Lindsey: Mmhmm.

Hank: That either one would give, would qualify you as having AIDS.

Lindsey: Yes.

Hank: But they are not, they have nothing to do with whether or not you have the virus. It's symptoms. It's if you've acquired a disease that you would not otherwise have, or if you have uh, less than 200 CD4 T-cells per microliter of blood. Oh, that's crazy, cuz that's just like that's just an analytical test. It's not, you know. It's not, it's not actually, it's just a threshold that is defined by us, as this is AIDS. I would not have thought that. Things that I am surprised I didn't know...

Lindsey: I'm here to teach. 

Hank: ...with Lindsey Doe.

Lindsey: Haha.

 Special Guest

Hank: [laughs] So, uh, this is fascinating, uh, but I think we need an uplift...

Lindsey: Yeah, this is not so sexy for you?

Hank:...which is going to come in the form of a chinchilla.

[ Special Guest card]

Hank: What? It's a chinchilla!

Jessi Knudsen Castañeda: [laughs] Surprise! 

Hank: Oh my gosh.

Jessi: Meet Ash, the chinchilla. 

Hank: Hi, Ash the chinchilla.

Lindsey: Hello, Ash.

Jessi: Ash is very uplifting cause he's super-duper cute. Look at his ears.

Hank: You are super cute. You're like 90 % head.

Jessi: [laughs] I would like you guys to feel him. Do you wanna touch him?

Lindsey: Awwww!

Hank: Oh my god, it's the softest thing in the world!

Jessi: You're correct.

Hank: Is it actually the softest thing in the world?

Jessi: The softest thing in the world. Softest animal in the world. I don't know about thing, but I know my animals, and this is the softest animal in the world. Um, in close competition with the sea otter. Um, but these guys have, the reason that they're soft is because of this hair obviously...

Hank: Yeah.

Jessi: But they have 80 hairs per follicle. 

Hank: What?

Jessi: So to put that in comparison, if we look at our arm...

Hank: Yeah, I've got one.

Jessi: ...we have little pores all over our skin, right. We have one hair per follicle, per pore. He has 80 hairs for every single follicle.

Hank: I had not even thought that that was a thing that could happen, to have more than one hair per follicle, and the idea that you could have 80...

Jessi: Yeah, 80, at most.

Hank: ...and probably you have way more follicles than we do.

Jessi: He has tons of follicles, and I'm not sure the exact count of follicles, but...

Hank: Yes, you have a lot of hairs...billions.

Jessi: It's impressive that his fur is so dense and he, so he's gonna use his fur to keep warm, and uh, there's a couple things about this fur though that if he, he does not wanna get wet. It's very difficult for him to dry off because he has such thick, dense fur. So instead of bathing in water, he's gonna groom himself with his mouth a little bit, but instead of bathing in water, he's gonna bathe in volcanic ash, hence the name Ash. So, what he's gonna do is, it's very, very fine dust, volcanic ash, and he's going to roll around on his back and squiggle and squirm and make this big dust storm and he's gonna get that dust in between each one of those hairs, making it, separating them and coating them and making them so they won't clump together. Um, and that's what's making him clean and extra furry and fluffy and it's going to make sure that he doesn't get too cold. Now, it's easy for him to overheat.

Hank: Mmhmm. 

Jessi: So, he's going to use his ears to help him temperature- regulate.

Hank: Vent some, some heat.

Jessi: Yeah, see there's not much fur on those ears.

Hank: Mmhmm.

Jessi: Um, and actually if you look closely you can see the blood vessels in those ears.

Lindsey: Hmmm.

Hank: Yeah, I see you're, that's weird.

Jessi: He doesn't like his tail touched.


Jessi: So...

Lindsey: No consent, I'm sorry, you don't consent.

Jessi: So, he's gonna use those ears to temperature regulate because he's gonna put them up away from his body and try and catch a breeze. So, it's gonna cool down the blood in those ears which is then going to circulate through his body and cool down his whole body. All right, so these guys, some cool, fun facts about them. They're crepuscular. Do you know what that means?

Hank: Crepuscular. It's like, like blood vessels, no corpuscles. That's a different thing.

Jessi: Not blood vessels, no. Crepuscular is about when they're awake.

Hank: Oh, ok.

Jessi: ...what time of day. So we have diurnal, we have nocturnal, and then, randomly, crepuscular is that other name for it, in between those two. 

Lindsey: Twilight?

Hank: What is that? 

Jessi: Twilight. 

Hank: Oh, twilight.

Lindsey: Wooooo.

Jessi: Day, yeah, uh, sunset and sunrise. That's when these guys are gonna be most active, and they're gonna be running around up in the mountains up there and they have really big back legs. You can't, they look like a really big ball of fur, but actually if you can, there's an indent right here and you can see that they're, they have a knee bone. And these guys can jump about 3 or 4 feet in the air. They're good springers. They use this...

Hank: Thanks for not doing it while you're here.

Jessi: Yeah. They use this tail to help keep their balance as they're running and jumping through the, their terrain there, um. And that's going to help them run really fast and not fall down and slip. They're gonna be running away from things that are also crepuscular, like different kinds of wild dogs, or owls and things like that. We're gonna go ahead and let him go back and cool off.


Hank: Ok. He's gotta go cool off.

Jessi: Yes.

Hank: Thanks for bringing uh the, bringing us back up, and thanks for bringing Ash in, Jessi.

Jessi: Thank you for having us.

Hank: And Lindsey, also, thank you...

Lindsey: You're welcome.

Hank: ...for joining us on SciShow Talk Show. And if you want to keep getting smarter with us here at SciShow, you can go to and subscribe. 

[Outro music]