Previous: Why Do Cats Knead?
Next: Cannibalism, Zombies & Suicidal Cells: The Latest In Cancer Research



View count:152,142
Last sync:2023-11-01 05:15
Nick Jenkins talks with Hank Green about selective breeding, with special guest Jessi Knudsen CastaƱeda.

Nick Jenkins:

Jessi Knudsen CastaƱeda:

Help support us by subscribing to our page on Subbable:
Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records:
Looking for SciShow elsewhere on the internet?

Thanks Tank Tumblr:

[Intro Music]

Hank: Hello, and welcome to the SciShow Talk Show, the day on SciShow where we talk about stuff with cool people. Today we're going to be talking to Nick Jenkins. Nick is the technical director for our office. He does CrashCourse, he does, uh, and he also fathers, uh, this little thing-

Nick: My buddy.

H: -who's Abby. Abby is a Corgi. What kind of Corgi is Abby?

N: Abby is a Pembroke Welsh Corgi.

H: Okay.

N: So there are two kinds of Corgi: there's Cardigan and the Pembroke. Um, not the same breed. They're complete-two completely separate breeds.

H: They're similarly cute. 

N: Similarly cute, yes. And the word Corgi actually means, uh, dwarf dog.

H: Oh! 

N: "Cor-" means dwarf or midget in Welsh and "-gi" means dog, and so they're both dwarf dogs, um, but one is from Pembrokeshire and the other's from Cardigan.

H: And is the difference the tail?

N: Uh, the tail is one of the differences, also the-the size, uh, Cardigans are bigger than, uh, than Pems, and, uh, also, uh, Cardigans have bigger ears.

H: Okay.

N: Um, they're sort of floppy. And their personalities are very different. So, like, the personality of a Cardigan is usually a lot more slap-happy and-

H: Mm-hm.

N: -um, clownish. Whereas Pembrokes are much more serious. [laughs] About their - about their work.

H: [laughs]

N: Um.

H: They do have work. They were bred as work dogs-

N: They were!

H: -not just to be cute.

N: No, and that was what I wanted to talk about today, actually- was whenever Abby, uh, shows up on CrashCourse or on Sexplanations-

H: Mm-hm.

N: -um, there are - or on, like, Michael Aranda's channel, where ever she shows up - there are always people in the comments that talk about how they're bred to be cute, and they weren't. 

H: Mm-hm.

N:They were actually bred to be working dogs. Um, they were actually the first herding dog. They're the oldest herding dog, and the reason that they're bred this way - the reason they have the short legs-

H: Uh-huh.

N: -the reason they have no tail, um, the reason they have big ears is all based on that. Um, so they have the short legs so they can get out of the way of kicking cows and kicking sheep and, stuff like that-

H: Yeah.

N: and they can just sort of roll with it. Uh, the big ears are to keep them alert.

H: Yeah, cause, yeah. Sheep and cows are designed to kick when they are threatened-

N: [laughs] Yes. Yeah.

H: -but they are generally designed to kick things that are taller than that.

N: Yes, absolutely.

H: So they just- right over the head.

N: Yep.

H: So kind of the opposite of Greyhounds who are - they are bred for hard work, Greyhounds. I have a Greyhound.

N: Yeah.

H: Uh, but not...sturdy dogs.

N: No, no.

H: They're - they're op- They're designed to operate for, like, two years, max.

N: Right.

H: And then, they're very, like, paper-thin skin. 

N: [laughs]

H: We live in Montana, and she can't go- like, we go on a hike, and she comes back bleeding from six different holes. (laughs)

N: [laughs]

H: Um, and also completely differently shaped.

N: Yes.

H: Opposite shape. 

N: And this brings up something that I wanted to talk about, which was selective breeding. 

H: Yeah.

N: If you look at where dogs are from, and what jobs they did with people, you start to see that, you know, all these different dogs had purpose. 

H: Mm-hmm.

N: Um, and this particular dog, it's purpose was to work all day.

H: Mm-hmm.

N: I mean it would, it, that she could put in an eight hour day better than I could. Um, she just has nonstop energy. Instead of it, uh, happing [laughs] happening naturally-

H: Yeah.

N: Um, you have a breeder, somebody like you or me, who are, just basically say, "I like this trait in this dog so I'm gonna find two dogs that have that trait-

H: Mmm.

N: and then I'm gonna breed them. Um, and so you try to maximize that, that particular trait. I mean, it sounds simple but it's-

H: Yeah, I mean you're al-al- also, I think, generally selecting for more than one trait at a time.

N: Right.

H: You're looking at, you know, how, like, you know, the size, the ability, and maybe you're not saying like this dog, uh, "I want a short dog, uh, let's go for that one"-

N: Mm-hmm.

H: But you're saying, "I want a dog that works hard and I want a dog that operates well and one that, you know, uh, has done good for me for these last ten years."

N: Right.

H: And so you take that dog and you try and, you know, get its genes in as many babies as possible.

N: Exactly. That is exactly correct.

H: So, it's not like we start out saying, "We want to create a Corgi! How are we gonna do that?"

N: No.

H: Though we could do that.

N: Yes, we could.

H: But that is not how it happened.

N: No. You start just sort of looking at it and saying, "Okay, well, I live in the desert. I need a dog that is-"

H: Mm-hmm.

N: "you know, gonna be good at, you know, cooling itself" or whatever. You can start that way. Or you can just say, "This dog, in particular, was really good. So I want to try to breed this dog to get more of this dog".

H: Right.

N: So, it's really, really, um, and yeah, with them, it's "I want a dog that hears well, I want a dog that is rough and tumble, I want a dog that has a great personality, or a personality that is work-centered-"

H: Mm-hmm.

N: "that, um...". So there's a lot of things we're breeding for. But the problem is that when you do selective breeding, you also, sort of, encourage disease.

H: Yeah, you can.

N: Well, yeah, you can-

H: Yeah.

N: -encourage disease. Selective breeding has given us great dogs and a great number of dogs but it can also, it starts to become more, a little bit more, like inbreeding.

H: Yeah.

N: So the recessive genes start to get more and more into the mix.

H: Mm-hmm.

N: So.

H: Um, the crazy thing to me with selective breeding is how fast we can do it.  It's not really been that long that we've been doing it and we have so many breeds and they're so different.

N: So different. It sort of is a weird thing when you link it to, um, a lot of what Darwin talks about. Because it's, like, theoretically, it shouldn't be possible to produce this much variation in that short of a time.

H: Right.

N: But, obviously, we can.

H: Yeah. It- It turns out-

N: [laughs]

H: that genetics is much more complicated-

N: [laughs] Yes!

H: -than we thought it was going to be; which is really cool and it means we have a lot more to study and a lot more to learn. I'm- I'm also really fascinated by, and I don't think that this is known, uh, how we breed instincts into a dog- behaviors. Uh, you know, obviously a Greyhound, uh, behaves very differently from a Corgi. Uh, like, just the fact that, you know, like herding dogs versus hunting dogs. All of these, like what you would think of as trained behaviors aren't, in fact, trained.

N: Mm-hmm.

H: They are just instinctual.

N: Absolutely.

H: And how the heck did we implant, how did we, like how did we, not just selectively breed the body but also the mind?

N: Exactly.

H: Fascinating.

N: Because yeah, if you took the Corgi out to a cattle ranch-

H: Yeah.

N: you worked with somebody who knew what they were doing, that Corgi would be herding in probably about twenty minutes.

H: Yeah.

N: Not so much for the Greyhound.

H: No, no, no, no.

N: A lot of other dogs would get out there and just be like, "I don't know what I'm supposed to do..."

H: Yeah it would be [?]....

N: "but everybody's yelling at me."

H: Might run away from or toward or probably just lay down.  

N: Yeah! [laughs]

H: [laughs]

N: That's probably true! [laughs] Yeah.

H: [laughs] Yeah.

N: Um, but yeah. That, that is another thing. It's like you're not just breeding for body, you're breeding for having the best dog to do a particular job.

H: Yep.

N: You know? In that case, her job is herding and guarding ranches, very alert, like there are times we'll all be sitting around playing games and nobody will hear anything and she will go nuts 'cause she heard something. So --

H: She knows what's going on.

N: These big radar dish ears, y'know are really good for that.

H: Oh my god she is so happy.

N: She's so happy right now.

H: And that could have sex with a wolf and make a baby --

N: Yup.

H:  -- that is fertile.

N: [laughs]

H: That is crazy.  What would you call that?

N: You want us to get you a wolf boyfriend?

H: No, that's a terrible idea.

N: [laughs]

H: You get a bunch of, a herd of worgis.

N: Worgis.  Send out your worgi raiders.

H: [laughs] That's terrifying.  I'm sure it would be adorable.

N: But yeah, I mean, the thing for me is there are all sorts of breeds of dogs, many, many breeds of dogs.  Dogs are the most varied, I believe animal, certainly mammal.

H:  Oh yeah, I mean, well I mean, if you're just talking about body shapes.  There's, I can't imagine going from Chihuahua to Great Dane.  Like, how could you get more var-?

N: How is that the same animal?

H: Yeah.

N: Yeah.

H: And yet...

N: 'Cause if you look y'know in the jungle, you're probably not going to see that amount of variety...

H: No no, that never happens.  That, no, it's, it's... It's impossible for that to happen without, um, sentient influence. 

N: Right.

H: But, uh, I, think we've done a great thing in the creation of dog breeds, though I am occasionally confused and perplexed by why we create certain breeds of dogs.  Uh, but...

N: Well there are many dogs like, uh, the bulldog that in creating them we've also created a problem like many bulldogs can't give natural births to their puppies.

H: Uh huh.

N: They have to have Cesarean.

H: Wow.

N: Because the dogs' heads are so big.

H: Yeah, that doesn't make any sense.

N: So there, y'know there are things like that so if the dog runs away and gets pregnant, it could, it could die.

H: Right.  Yes, eh uh, I've actually heard that if you let dogs just sort of interbreed for a few generations, they end up all looking the same.  It's a dog that has basically, you breed the breed out of it and it immediately becomes just, what, just a wild looking dog.  Like a small, brown, lab mix-y looking thing.

N: Yup.

H: Which we have lots of.

N: We do, especially here.

H: And they are often very good dogs.

N: Yeah, they are.

H: [laughs]

N: Um, so just to wrap up here, I mean, what I want to say is, you know, corgis are really popular, they're really energetic, they're very alert, they need a lot of exercise, long walks.  Um, they are adorable, but you know, definitely know what you're getting yourself into.  They are a big dog in a small body.  Actually they are a big dog with small legs, really.

H: [laughs] Yeah, yeah, a little bit. Hi hi hi hi, did you want me to pet you on the head.  Okay, thank you, Abby.

N: Is that what you wanted?

H: Thanks for being a special guest.  Uh, Jessi from Animal Wonders is going to come and talk about her own selective breeding program that she's got going on at Animal Wonders, which I think will include some adoreableness.  Abby, you have to behave yourself, because this will be your natural prey.

N: I think we're gonna put you away.

H: Okay, let's do that.   That's probably a better idea.

H: This is Sweet Pea, who is the cutest rat I've ever seen, and this is Ebeneezer.  And they are rats. Um, I've never, like, I like rats, I know that not everybody does so I apologize to those people, but I love rats, um and I have had several friends who have, really have had really wonderful relationships with their rat pets. Um, but I don't think I've ever seen anything as cute as this in the rat family. Just the fur is, like, such a cool color and the eyes are so big and the nose is so cute. And the big ears.

Jessi: She does have big ears, doesn't she?

H: Oh, are we friends? Oh, hi oh, oh yes sniff sniff sniff, yeah I like you too. Don't bite me.

J: So you guys were talking about selective breeding and, um, rats are selectively bred.

H: Of course, yeah.

J: From--they originated from the black rat which came to the Norway rat and we've gotten lab rats from them, but we've also gotten the fancy rat. The fancy rat is our pet rats that we have today, and there's several different breeds of these guys, there's just the regular then there's the satin and there's the velvet, those are different coats.

H: Mmm-hmm.

J: And then there's rex, um, but then there's also different patterns.

H: Mmm-hmm.

J: There's the albino, and then there's hooded, and there's speckled- [laughs]

H: Where ya going? Come here.

J: I'm going into this dark hole!

H: Oh, you're fast, huh. There you go, its fine.

J: There ya go. But what, what we have two traits that that we're looking to selectively breed at animal wonders, which I have fun with, is um her ears are going to be a little different than a regular rats ears. These guys are what we call dumbos. And their ears have switched from being on top of their head to on the side of their head

H: Oh, okay

J: And they look extremely large

H: So Ebeneezer, uh, has curly coat.

J: Yeeeaaaah, and this is called a rex coat or curly, and they're gonna have wavy fur, and then their whiskers are going to be a little bit curled.

H: Yeah! That's so cute!

J: Yeah. Now he's not an albino, and can you tell why?

H: Uh, because his eyes are black.

J: Yeah, so he does have pigment, he also has one black spot on top of his head. so he is not an albino. Now, we bred him-here you go, Nick-

N: Oh, thank you. I get my own rat.

J: [laughs] To a regular, just she was a tan, hooded rat, and she created Sweet Pea- they created Sweet Pea- and... Scrooge.

H: Oh. Okay. You got the, the, the curly whiskers.

J: Curly whiskers and that wavy fur.

H: Uh huh.

J: Now they both have those dumbo ears, they have dumbo ears, so you can see that Scrooge got a lot of the traits from his dad, and not so much from his mom. And Sweet Pea got a lot from her mom, but not much from her dad.

H: Fascinating.

J: So its just interesting, y'know they can be in the same litter, and these guys were actually in different litters, um, but the same genes-

H: Right.

J: from mom and dad were coming. So-

N: So now his eyes are pinker.

J: Yeah, so he is an albino.

N: He's actually an albino.

J: He is an albino. And it's kinda dark, I mean, you can't see it very well, but he does have-

N: Yeah, it's really subtle.

J: He does have pink eyes.

H: Mmm hmm, mmm hmm.

J: Now I'm gonna bring out- I brought some other little babies, so just so you could see the ear shape.

H: So what do we have here?

J:  I wanted to show you a normal-eared rat, right next to Scrooge.

H: Okay, yeah, uh huh.

N: Oh, yeah!

J: And you can see how those ears are perky on top of her head there, and then Scrooge's have come down onto the sides. And so that's a dumbo rat and then a regular rat.

H: Okay. That's crazy.

N: Were, were any of these from the same litter?

J: This one came from a completely different-

N: Oh, okay.

J: Completely different. Um, I have-

H: Ooh!

J: a little handful, that, of my newest litter here.

H: Tiny baby tiny rats.

N: Ooooh.

J: Itty bitty baby rats.

H: Ahhhhhh.

N: Cuteness overload!

J: These are all the same pups from the same litter.

N: They look like little furred pigs.

J: [laughs]

H: Oh my gosh. 

J: And they're all Ebeneezer's babies.

N: Look at your kids!

J: [laughs]

H: So, why do you, uh, why do you breed for these traits? Just for-

J: Why do we breed them-

H: cuteness?

J: Yeah, just for cuteness. There's no real reason to do it. It's not gonna help them survive. It doesn't make them, you know, tastier. [laughs] It doesn't make them, you know, more friendly. It just, uh-

H: Yeah.

J: It's just for cuteness factor and um-

H: Well, you did get that.

N: Yeah!

H: You got the cuteness factor.

J: Super cute.

N: We got cute going on. Cute, cute has been achieved.

H: Yep.

J: [laughs]

H: I wish I could have you in my house, but my cat would eat you.

J: Mmm hmm. 

H: Immediately.

J: We had a cat and a rat that were really good friends.

H: [gasps] Awww.

J: Yeah, it was Dai- her name was- [laughs] Rat was Daisy- want me to take it back?

N: Yeah.

J: Yeah, aw hey, you want baby?

N: Sure! Oh ho gosh.

J: [laughs] 

H: You can't even feel it.

N: It's so adorable. Hi.

J: So, the rat and the cat were actually really good friends, and they would take turns chasing each other in play. And so the cat would run after the rat, and the rat would run, and then it would stop, and the cat would stop and go--

H: Tap.

All: [laugh]

N: You're it.

J: And then the rat would turn around and chase the cat into the other room.

H: That-

N: They were really playing tag.

J: They were really having fun. It was really cute.

H: That is not the experience I have had with my, with my cat.

J: They grew up together, though.

H: She plays, uh, not nice games.

J: [laughs]

H: With all of the rodents she has found thus far.

J: Fun for her. Fun for her.

N: More instinctual games?

H: Yeah.

N: Yeah.

J: Yeah.

H: She, uh, she actually- I don't, I don't think has ever killed one, but she doesn't- it's not, it's not plea- it's not nice play.

J: Hm, playing with her food.

H: Yeah, she bites them and then lays down on them.

J: [laughs]

H: It's like-- Feels them wiggling underneath her belly. I don't know what this behavior is, but it's very strange.

So, thank you to Ebeneezer and Scrooge, father and son here. Um, and thank you to you for watching this episode of SciShow Talk Show. Uh, Jessi from Animal Wonders, as always you're amazing. I can't believe you have so many cool things to share with us. If you want to check out her YouTube channel, it is linked in the description below. Nick, thank you for sharing your insights and your Corgi with us.

J: Yes.

H: Uh, if you want to keep getting smarter with us, you can go to and subscribe.

N: This thing is so cute!