WEBVTT - Evolution of the Anus 0:00:03.040 --> 0:00:06.119 Welcome to Stuff to Blow your Mind from how Stuffworks 0:00:06.120 --> 0:00:14.800 dot com. Hey, welcome to Stuff to Blow your Mind. 0:00:14.840 --> 0:00:17.239 My name is Robert Lamb and I'm Joe McCormick and 0:00:17.320 --> 0:00:19.279 Robert I got a question for you. What do you 0:00:19.280 --> 0:00:23.040 think is the most underrated body part on the human 0:00:24.480 --> 0:00:26.079 You could go in a lot of ways, right, you 0:00:26.160 --> 0:00:30.840 really can. I mean, certainly, we we tend to put 0:00:30.840 --> 0:00:34.159 more emphasis on the brain and the heart, and then 0:00:34.159 --> 0:00:37.239 of course throughout human history confused the two and the 0:00:37.320 --> 0:00:39.720 role they might play. Uh, you know, I think back 0:00:39.760 --> 0:00:43.080 to the the the ancient Egyptians and their idea that 0:00:43.560 --> 0:00:45.680 the heart was far more important than the brain, and 0:00:45.720 --> 0:00:48.839 the brain was just to be removed and discarded, whereas 0:00:48.920 --> 0:00:53.920 the heart had a privileged place in the funeral preparations 0:00:54.000 --> 0:00:56.880 of dead pharaohs. But of course it's impossible for us 0:00:56.880 --> 0:00:59.480 to underestimate the value of the heart and the brain 0:00:59.560 --> 0:01:01.840 now since we know them to be so important. But 0:01:01.880 --> 0:01:03.920 there are all kinds of body parts you have that 0:01:03.960 --> 0:01:06.680 you probably just don't stop to be very thankful for 0:01:06.959 --> 0:01:09.240 or think about very much, but they do you a 0:01:09.240 --> 0:01:12.520 lot of good. I think about the underrated facility of 0:01:12.560 --> 0:01:17.959 the toes. Yeah, yeah, to toes are granted toes maybe fetishized, 0:01:18.000 --> 0:01:20.520 as as can any part of the human anatomy. Oh no, 0:01:20.600 --> 0:01:22.240 I didn't mean that way. No, I mean they're like 0:01:22.400 --> 0:01:26.240 usefulness and balance and movement. Oh yeah, yeah, certainly, but 0:01:26.240 --> 0:01:28.000 but it's not something that we tend to attach our 0:01:28.040 --> 0:01:31.480 identity to. Whereas the brain. Yeah, I mean our podcast 0:01:31.560 --> 0:01:33.800 has had a brain on its logo in the past. 0:01:34.160 --> 0:01:37.160 You know, the heart has all these symbolic meanings where 0:01:37.240 --> 0:01:40.120 we want to attach our identity to them in addition 0:01:40.160 --> 0:01:43.520 to the functions that they play. But then there are 0:01:43.520 --> 0:01:46.120 parts of the body that we generally don't want to 0:01:46.160 --> 0:01:50.000 think about, and we don't think about unless they are 0:01:50.040 --> 0:01:52.920 giving us grief, unless there's something wrong with them, and 0:01:52.960 --> 0:01:55.840 then they become the center of our existence. Right. It's 0:01:55.880 --> 0:01:58.040 the same way that you never think about your internet 0:01:58.080 --> 0:02:01.120 connection unless it's not working. Right. There are parts of 0:02:01.160 --> 0:02:03.440 the body that you probably just never think about unless 0:02:03.480 --> 0:02:05.760 something's going wrong, right, or we go to great pains 0:02:05.800 --> 0:02:07.520 not to think about them. You know, we kind of 0:02:07.560 --> 0:02:09.880 have all these blinders up. Really, the part of many 0:02:09.880 --> 0:02:12.520 and animals anatomy that we're going to discuss here today 0:02:12.720 --> 0:02:16.480 the anus. The anus today it's anus science on stuff 0:02:16.520 --> 0:02:18.640 to blow your mind, right, and I I wanted to 0:02:18.680 --> 0:02:22.280 do this episode really since I guess that's when I 0:02:22.320 --> 0:02:25.320 really first found out about anus. Is. Yeah, I had 0:02:25.320 --> 0:02:27.280 no idea. I had no idea what it would happened. 0:02:27.320 --> 0:02:30.040 And then I read this, uh, this cool science paper 0:02:30.160 --> 0:02:32.280 and I was like, whoa, this is this is this 0:02:32.320 --> 0:02:33.840 is where it all comes from. This is this is 0:02:33.880 --> 0:02:36.240 the center of all the activity. I really appreciate you 0:02:36.280 --> 0:02:38.840 suggesting this topic because the anus turned out to be 0:02:38.919 --> 0:02:42.000 far more interesting than I had ever imagined it is. 0:02:42.160 --> 0:02:44.160 And that's what we're going to try and outline in 0:02:44.200 --> 0:02:46.440 this this episode. Now, we we do have to drive 0:02:46.520 --> 0:02:48.959 home since we are talking about the anus and there 0:02:49.040 --> 0:02:52.280 is there's just so much not not really. I don't 0:02:52.280 --> 0:02:55.160 think taboo is going to be a stumbling block for 0:02:55.240 --> 0:02:59.040 us here, but the anus is so tied into our 0:02:58.840 --> 0:03:02.600 our systems of humor, Like it is so giggle inducing. 0:03:02.600 --> 0:03:05.200 When you when you saw this title pop up on 0:03:05.280 --> 0:03:09.200 your your your your device or whatever program you used 0:03:09.240 --> 0:03:11.440 to listen to your podcast, you may have giggled at 0:03:11.480 --> 0:03:14.919 the prospect of listening to say in an hour's podcast 0:03:15.240 --> 0:03:18.240 about the anus. Yeah, you'll probably notice that we talk 0:03:18.320 --> 0:03:20.519 about biology a lot on the podcast. I've gotten to 0:03:20.520 --> 0:03:23.480 where it's extremely easy to talk about, say, the biology 0:03:23.480 --> 0:03:26.119 of sex, without making any jokes. That's something a high 0:03:26.120 --> 0:03:28.040 school or might not be able to do. But you know, 0:03:28.080 --> 0:03:30.360 when you talk about it enough, it's just an interesting 0:03:30.400 --> 0:03:33.639 subject on its own. Well, sexist is its humor appeal? Well, 0:03:33.639 --> 0:03:36.400 sex is one of these things. Sexual reproduction is a 0:03:36.440 --> 0:03:39.600 case where I feel like most people, at least, you know, 0:03:39.680 --> 0:03:44.080 most adults are capable of having both a humorous conversation 0:03:44.120 --> 0:03:48.000 about and a serious conversation about. You reach that point 0:03:48.000 --> 0:03:52.120 where you realize there is this entirely serious side to 0:03:52.240 --> 0:03:55.040 the discussion, and you can switch back from one and 0:03:55.120 --> 0:04:00.000 the other. But with the anus, there's it's almost gotten there. Yeah, 0:04:00.000 --> 0:04:04.400 it's almost all humorous, unless you yourself are are a 0:04:04.800 --> 0:04:09.480 proctologist or or or just a medical professional, or you 0:04:09.560 --> 0:04:13.080 have had to deal with health issues related to the anus. 0:04:13.080 --> 0:04:17.240 Otherwise it's just all the realm of body humor. Or 0:04:17.279 --> 0:04:20.080 maybe you're somebody who studies the evolution of the anus, 0:04:20.120 --> 0:04:22.679 which is something that we will definitely be touching on today. 0:04:23.040 --> 0:04:26.359 These questions about whence this hole in the backs of 0:04:26.360 --> 0:04:29.080 our bodies? Where does it come from? And what is 0:04:29.120 --> 0:04:31.320 it doing. That's not so much what is it doing 0:04:31.360 --> 0:04:34.039 that's pretty obvious, yes, but but the way that it 0:04:34.120 --> 0:04:36.160 does it, the way that it's come to do it, 0:04:36.560 --> 0:04:40.080 and just how how it functions. Uh, hopefully you will 0:04:40.160 --> 0:04:44.400 leave this this episode with a whole new respect for 0:04:45.080 --> 0:04:47.839 the anus of any animal. Okay, Now we wanted to 0:04:47.880 --> 0:04:50.680 start with an interesting fact, Robert, that you came across, 0:04:50.720 --> 0:04:54.800 actually a curious little book that you found on the internet, right, 0:04:54.920 --> 0:04:58.200 that's right. So I was casting about for some mythology 0:04:58.240 --> 0:05:00.080 related to the anus and we'll we'll get to some 0:05:00.120 --> 0:05:03.120 of that later on gods and so forth. Yeah, yeah, 0:05:03.520 --> 0:05:05.400 I figured, you know, it's always good to throw in 0:05:05.440 --> 0:05:09.080 a little mythology a few monsters when we can. And 0:05:09.120 --> 0:05:12.000 I was just plugging in different ancient cultures. I plugged 0:05:12.040 --> 0:05:14.600 in the ancient Egyptians to see what what was up, 0:05:14.600 --> 0:05:17.080 and I ran across this book, The herbal Lore of 0:05:17.160 --> 0:05:20.480 Wise Women and Warp Cunners The Healing Power of Medicinal 0:05:20.520 --> 0:05:24.359 Plants by wolf D. Storrel, and he points out that 0:05:24.360 --> 0:05:27.440 the doctors of ancient cultures were part of the priesthood, 0:05:27.480 --> 0:05:31.320 and for the ancient Egyptians, each physician was responsible for 0:05:31.400 --> 0:05:35.760 curing only one illness. So the pharaoh was attended by 0:05:35.800 --> 0:05:39.920 such specialist as the Royal Keeper of Pharaoh's left eye, 0:05:40.040 --> 0:05:42.960 the Royal Keeper of the Pharaoh's right eye, and then 0:05:43.120 --> 0:05:46.880 most importantly of all, perhaps the shepherd of the royal 0:05:46.920 --> 0:05:51.880 anus or the nerofoot. If I am reading that correctly, 0:05:52.240 --> 0:05:55.200 the Shepherd of the Royal anus. Now laugh, you may laugh, 0:05:55.279 --> 0:05:57.799 you may, but this is actually a kind of interesting 0:05:57.800 --> 0:06:01.280 because it's an early example of medical special realizations, something 0:06:01.320 --> 0:06:04.120 that we've seen again in the modern world. There are 0:06:04.120 --> 0:06:07.839 a lot of reasons that a pharaoh might have need 0:06:07.960 --> 0:06:11.839 needed to have a special attendant to problems dealing with 0:06:11.880 --> 0:06:15.000 their anus, because a lot of the problems you can 0:06:15.120 --> 0:06:17.840 have with your ans can be related to, say, certain 0:06:17.880 --> 0:06:21.200 types of over indulgent diet. Yeah, I mean just in general, 0:06:21.279 --> 0:06:24.560 there's just so many digestive ailments they can occur in 0:06:24.640 --> 0:06:26.760 one's life. You see this pop up in a number 0:06:26.800 --> 0:06:30.560 of different traditional practices, for instance, moodras. Are you're familiar 0:06:30.600 --> 0:06:34.000 with moodra's, I'm not sure. So this is a whenever 0:06:34.040 --> 0:06:36.200 you see someone in a yoga pose and they're making 0:06:36.279 --> 0:06:38.560 or they're a meditative state and they're making a particular 0:06:38.720 --> 0:06:41.640 little hand uh motions. They're holding their fingers together in 0:06:41.640 --> 0:06:45.440 a particular pattern. That is a moodra And I've read 0:06:45.520 --> 0:06:47.080 up on them in the past, and when you start 0:06:47.120 --> 0:06:49.240 looking at the different moods that they have them for 0:06:49.320 --> 0:06:53.440 different things, it's you know, it's about channeling energy and whatnot. Uh. 0:06:53.520 --> 0:06:56.320 But it seems like most of them are related to digestion, 0:06:56.920 --> 0:07:00.120 which which makes sense when you when you think about 0:07:00.160 --> 0:07:03.680 all the digestive ailments that can afflict an individual over 0:07:03.720 --> 0:07:06.360 the course of their lifetime. Totally, now the sky's storial 0:07:06.480 --> 0:07:09.120 that I want to say, this book does appear to 0:07:09.200 --> 0:07:12.160 be kind of in a liminal or less than totally 0:07:12.200 --> 0:07:15.240 authoritative space. I think this guy deals in some some 0:07:15.440 --> 0:07:18.880 kind of natural apathy areas and stuff. But it was 0:07:19.040 --> 0:07:21.800 curious and had some fun ideas in it. Yeah, he's 0:07:21.840 --> 0:07:24.720 he's not an Egyptologist or anything. But but I I 0:07:24.840 --> 0:07:26.600 have to point out that I did find this bit 0:07:26.600 --> 0:07:28.880 about the Shepherd of the Royal Anist backed up in 0:07:28.960 --> 0:07:31.120 some other works, including Medicine in the Days of the 0:07:31.200 --> 0:07:37.880 Pharaohs by dermatologist Bruno Hella and cardiologist Bernard Ziskins from 0:07:37.960 --> 0:07:41.360 two thousand five. Yes, I think that fact is well attested, 0:07:41.520 --> 0:07:43.880 but also I just wanted to follow up on this 0:07:44.000 --> 0:07:48.200 other idea. In his book, Storial argues that every culture 0:07:48.360 --> 0:07:52.320 has a primary external metaphor that it uses to understand 0:07:52.400 --> 0:07:55.560 medical insights, which is like a model through which to 0:07:55.680 --> 0:07:59.280 visualize health and human function. So for the ancient Mesopotamians, 0:07:59.320 --> 0:08:01.840 he says, this moll was the movements of the planets 0:08:01.880 --> 0:08:05.080 through the zodiac. For the ancient Indians, he says one 0:08:05.120 --> 0:08:07.440 of the models they used most often was the cycle 0:08:07.560 --> 0:08:10.800 of the seasons from spring to pre monsoon to monsoon. 0:08:11.720 --> 0:08:14.600 And for the ancient Egyptians, this model, he says, was 0:08:14.760 --> 0:08:19.120 the Nile River quote regularly cleansing and fertilizing the thousand 0:08:19.200 --> 0:08:23.120 mile long oasis. Just as the Nile flows from Nubia 0:08:23.160 --> 0:08:26.920 to the Mediterranean, so the elementary tract, also known as 0:08:26.960 --> 0:08:30.240 the digestive tract, flows from the mouth to the organs 0:08:30.280 --> 0:08:33.960 of elimination in the human body, bringing health and cleaning 0:08:34.000 --> 0:08:37.719 out impurities. Now, upon reading this, I couldn't help but 0:08:37.840 --> 0:08:40.520 notice that if this is true, what what he says 0:08:40.559 --> 0:08:44.960 about the you know, this metaphor of human health being 0:08:45.040 --> 0:08:49.480 the Nile River, the Nile River delta, which is this lush, fertile, 0:08:49.640 --> 0:08:54.640 agriculturally productive region that sustains the civilization around it. In 0:08:54.760 --> 0:08:59.040 the metaphor, the delta would be the rectum in the anus. Yeah, 0:08:59.080 --> 0:09:01.160 this reminds me of something that that I was thinking 0:09:01.160 --> 0:09:03.920 about researching this topic as well. Like we think about 0:09:04.040 --> 0:09:07.959 the the the track of digestion in the human experience, 0:09:08.080 --> 0:09:12.160 the linear experience of digestion, uh, And I wondered what 0:09:12.320 --> 0:09:15.520 extent uh that plays a role and just our understanding 0:09:15.559 --> 0:09:18.440 of time. When we were talking about time in our 0:09:18.480 --> 0:09:22.560 episode that this present moment we talked about comparing time 0:09:22.720 --> 0:09:26.000 to the river we see flowing past us and so forth. 0:09:26.800 --> 0:09:29.160 But here we have this river flowing inside us that 0:09:29.320 --> 0:09:33.000 is an even closer uh metaphor, that's that makes itself 0:09:33.040 --> 0:09:36.200 readily available. So you're thinking, maybe if we had evolved 0:09:36.440 --> 0:09:39.240 to have large brains, but to not have a one 0:09:39.280 --> 0:09:41.880 way digestive tract instead to have I don't know, one 0:09:41.920 --> 0:09:44.280 of these open sack mouths We're going to talk about 0:09:44.320 --> 0:09:46.960 more as the episode goes on, where you just sort 0:09:47.000 --> 0:09:50.240 of like eat and digest and poop all through the 0:09:50.320 --> 0:09:53.160 same one orifice and sack. Would that lead us to 0:09:53.200 --> 0:09:55.840 have a different conception of sort of the the order 0:09:55.960 --> 0:09:59.760 of things in history, and the meaning of structure and 0:09:59.800 --> 0:10:02.760 our lives. Yes, I, as we proceed here, I challenge 0:10:02.800 --> 0:10:07.600 anyone out there too imagine an alien life woman, intelligent 0:10:07.640 --> 0:10:10.959 alien life form with one of these sort of rival 0:10:11.080 --> 0:10:15.280 digestive systems, and imagine how that rival digestive system might 0:10:15.600 --> 0:10:20.040 impact their perception of time or the universe. Take up 0:10:20.080 --> 0:10:24.920 the challenge. Alright, Well, on that note, we should probably begin, uh, 0:10:25.280 --> 0:10:27.839 well at the beginning or at the end if you'd rather, 0:10:28.320 --> 0:10:32.680 by discussing just what the anus is and what it does? Yeah, 0:10:32.760 --> 0:10:35.880 what is your anus and what does it do? Uh? 0:10:35.960 --> 0:10:38.679 The anus? Of course I shouldn't giggle, should I know? 0:10:38.880 --> 0:10:41.400 I think a little a little giggling is uh just 0:10:41.480 --> 0:10:45.080 cannot be avoided thanks human culture. The anus, of course, 0:10:45.400 --> 0:10:47.559 as we all know, is the point of termination for 0:10:47.640 --> 0:10:51.880 the digestive system. It's the exit point for solid waste 0:10:51.960 --> 0:10:53.840 in the body. And I think one of the things 0:10:53.920 --> 0:10:57.439 we should regularly stop and be thankful for is the 0:10:57.520 --> 0:11:00.640 fact that we have an anus. It does one job. 0:11:01.360 --> 0:11:04.400 It is dedicated to the elimination of solid waste. There 0:11:04.440 --> 0:11:08.520 are lots of complex animals that are not like this. Um. 0:11:09.000 --> 0:11:11.600 We are going to talk more about some simpler animals 0:11:11.679 --> 0:11:14.720 that have like a single opening through which everything takes place, 0:11:15.040 --> 0:11:19.360 but even complex animals like birds, reptiles, amphibians, monitory ms 0:11:19.840 --> 0:11:23.080 do not have an anus, but a cloaca, which serves 0:11:23.160 --> 0:11:27.200 as a general purpose opening for solid waste, liquid waste, 0:11:27.400 --> 0:11:31.240 and reproduction, kind of a fusing of the different categories 0:11:31.280 --> 0:11:34.520 together exactly. So, if you imagine we had evolved from 0:11:34.720 --> 0:11:39.200 birds instead of mammals, we would probably still defecate, urinate, 0:11:39.360 --> 0:11:42.360 and give birth all through the same hole. Now, maybe 0:11:42.400 --> 0:11:44.439 if that was how we were, we wouldn't mind, But 0:11:44.800 --> 0:11:47.680 I don't know. I think most humans are probably glad 0:11:47.760 --> 0:11:49.640 that things don't have to be that way. Well, I 0:11:49.920 --> 0:11:52.200 think we should also be thankful that humans don't yet 0:11:52.320 --> 0:11:56.199 have the power to decide like where their waste elimination 0:11:57.400 --> 0:11:59.800 or if this will be and how it functions, because 0:11:59.840 --> 0:12:01.880 we would we put it down there. We'd probably put 0:12:01.920 --> 0:12:04.319 it down there on our heel, so we could discreetly 0:12:04.400 --> 0:12:06.880 defecate as far from the rest of our our body 0:12:06.960 --> 0:12:10.760 as possible. I have often wondered that same exact thing. 0:12:10.880 --> 0:12:14.000 Why doesn't defecation happen at like the end of a 0:12:14.160 --> 0:12:17.960 tale or something? Something farther away from you. But then again, 0:12:18.000 --> 0:12:20.079 why would it need to And once you've got a 0:12:20.160 --> 0:12:22.400 tale that you need to defecate through, what happens if 0:12:22.400 --> 0:12:24.720 it gets chopped off something? And that will come up 0:12:24.760 --> 0:12:26.360 in this episode. Hey, it has come up in the 0:12:26.440 --> 0:12:30.360 previous episode. Uh, there's it's the anus is important and 0:12:30.440 --> 0:12:33.800 therefore it really needs to be core and center to 0:12:34.040 --> 0:12:36.720 the the primary trunk of the body. Now, if you're thinking, 0:12:36.840 --> 0:12:39.760 come on, guys, or if you're not on board yet, right, 0:12:39.840 --> 0:12:41.800 you know you're thinking, like, how can we really do 0:12:41.880 --> 0:12:44.120 an episode on the anus? It's just a hole that 0:12:44.200 --> 0:12:46.679 stuff comes out of. What could there be to say 0:12:46.720 --> 0:12:48.839 about it? I would say that the anus is a 0:12:48.960 --> 0:12:53.079 surprisingly complex organ, uh, and so I think maybe we 0:12:53.120 --> 0:12:57.000 should look at its complexity and what it has to do. Indeed, 0:12:57.120 --> 0:12:59.120 so as we dive in here, I want to turn 0:12:59.160 --> 0:13:01.800 to the words of Mary Roach, who wrote a wonderful 0:13:01.840 --> 0:13:05.400 book several years back, Gulp Adventures on the Alimentary Canal. 0:13:06.520 --> 0:13:09.319 I've referenced this in other episodes. It's just a wonderful 0:13:09.520 --> 0:13:14.760 exploration of human digestion and some additional topics. For instance, 0:13:14.760 --> 0:13:16.600 there's a whole section in the book where she talks 0:13:16.600 --> 0:13:20.480 about the practice of smuggling things in one's rectum and 0:13:20.679 --> 0:13:24.480 sort of the science of that practice. But here's a 0:13:24.520 --> 0:13:28.040 here's a wonderful quote where she talks about the anus quote. 0:13:28.080 --> 0:13:31.599 Anal tissue is among the most densely innervated on the 0:13:31.720 --> 0:13:34.640 human body. It has to be. It requires a lot 0:13:34.760 --> 0:13:37.800 of information to do its job. The anus has to 0:13:37.880 --> 0:13:40.439 be able to tell what's knocking at its door, is 0:13:40.520 --> 0:13:45.360 it solid, liquid, or gas, and then selectively release either 0:13:45.520 --> 0:13:48.400 all of it or one part of it. The consequences 0:13:48.480 --> 0:13:52.800 of a misread are dire. They certainly are. Now. Yeah, 0:13:53.360 --> 0:13:56.079 though I wonder I've had this thought before. Okay, So, 0:13:56.480 --> 0:14:01.520 in modern polite society, you don't want to just whoop anytime, right, 0:14:01.679 --> 0:14:03.480 you know, you want to be able to control that 0:14:03.640 --> 0:14:07.199 for like cultural and privacy reasons, and maybe for some 0:14:07.360 --> 0:14:11.600 hygiene reasons. But if you imagine us living in the wild, 0:14:12.559 --> 0:14:15.960 what's the reason that you would need to be able 0:14:16.040 --> 0:14:19.720 to control when you poop? Why does that matter? Well, 0:14:20.120 --> 0:14:23.120 I mean, controlling when you defecate is really important because 0:14:23.160 --> 0:14:26.000 outside of the particular human concerns, this is an issue 0:14:26.040 --> 0:14:29.720 of hygiene but also survival. Being able to choose where 0:14:29.800 --> 0:14:33.120 and how you defecate. It's tremendously important and it entails 0:14:33.200 --> 0:14:37.120 everything from not pooping where you eat, to say, pooping 0:14:37.160 --> 0:14:39.440 in a place where you can easily hide the stuff. 0:14:39.600 --> 0:14:42.400 That we see this every day, or at least cat 0:14:42.480 --> 0:14:45.600 owners do with a litter box, that the cat wants 0:14:45.680 --> 0:14:48.200 to poop where it can hide its poop because it 0:14:48.320 --> 0:14:53.920 has this uh evolved necessity to disguise the scent of 0:14:54.040 --> 0:14:57.360 its of its activity. And then also sometimes you want 0:14:57.400 --> 0:15:00.320 to produce the right sort of round poop that will 0:15:00.440 --> 0:15:03.160 roll away from your body. This is apparently the case 0:15:03.200 --> 0:15:05.600 with with goats. If you've ever been to a petting 0:15:05.680 --> 0:15:09.200 zoo with a child, for instance, you probably noticed that 0:15:09.360 --> 0:15:12.000 the round poop is basically falling out of the goats 0:15:12.040 --> 0:15:15.000 at all times. And uh and and that he's round 0:15:15.200 --> 0:15:17.000 so that it can roll away. Is this kind of 0:15:17.080 --> 0:15:19.040 like when it comes out sort of like a spray 0:15:19.120 --> 0:15:22.840 of coffee beans. Yeah, just kind of like tumbling coffee 0:15:22.880 --> 0:15:25.720 beans and the pebbles. Yeah. And apparently the purpose is 0:15:25.960 --> 0:15:28.320 these things would roll away. It's self hiding poop. They 0:15:28.360 --> 0:15:30.520 don't have to bury anything at all. Now I'm curious 0:15:30.520 --> 0:15:33.800 about what you said about the idea that controlling when 0:15:33.840 --> 0:15:37.200 you defecate plays a role in survival? What what would 0:15:37.280 --> 0:15:40.120 the role in survival be? Well, I ran across a 0:15:40.240 --> 0:15:42.480 paper a few years back because from two thousand thirteen, 0:15:42.600 --> 0:15:47.320 The Control of Defecation in Humans and Evolutionary Advantage by 0:15:47.480 --> 0:15:52.560 Italian bowl experts UH G. Besati and V. Villainacci, And 0:15:52.680 --> 0:15:55.880 it breaks down the particular human side of this. Uh 0:15:55.960 --> 0:15:58.360 and this is something I've explored before when I was 0:15:58.400 --> 0:16:01.240 looking at the Monster or Science of the Googlies. You 0:16:01.280 --> 0:16:05.360 remember Googlies right before film. The cover was a little 0:16:05.440 --> 0:16:09.000 monster popping out of the toilet. Yeah, tagline taste, They'll 0:16:09.000 --> 0:16:11.920 get you in the end. But it made me think 0:16:11.960 --> 0:16:15.040 it's like, all right, well, humans are are vulnerable when 0:16:15.040 --> 0:16:18.400 they're on the toilet. All animals are vulnerable to some 0:16:18.520 --> 0:16:23.800 extent when they are defecating. So how does evolution plan 0:16:23.880 --> 0:16:25.960 to all of this? Well, in this case, the authors 0:16:26.040 --> 0:16:28.920 point out that human fecal matter would have certainly put 0:16:29.000 --> 0:16:32.440 early humans at risk from the apex predators of your 0:16:33.200 --> 0:16:36.320 So if you run a human fecal sample, modern or ancient, 0:16:36.440 --> 0:16:42.440 through complex gas uh chromatographic or mass us spectrometric analysis, 0:16:42.720 --> 0:16:46.240 you'll discover that quote, human feces are rich in volatile 0:16:46.320 --> 0:16:50.560 compounds likely to be identified by potential predators. So volatile compounds, 0:16:50.600 --> 0:16:55.280 what does that mean? Smell? Yeah, And as we've driven 0:16:55.320 --> 0:16:57.960 home before on the podcast, I think our human sense 0:16:58.000 --> 0:17:01.360 of smell is rather limited, like we're seeing in grungy 0:17:01.440 --> 0:17:04.520 black and white, whereas something like an apex predator or 0:17:04.560 --> 0:17:07.159 something like even our our pet dogs and cats, especially 0:17:07.240 --> 0:17:11.160 the dogs, they have an entirely different, like full color 0:17:11.359 --> 0:17:14.200 HD experience of things. Well, Robert, have you ever owned 0:17:14.240 --> 0:17:16.240 a dog. It's been a very long time. I've mostly 0:17:16.280 --> 0:17:18.520 been a cat owner my entire adult life. I think 0:17:18.680 --> 0:17:21.080 most people who have dogs will know what I'm talking about. 0:17:21.280 --> 0:17:23.840 Dogs love poop. They want to smell all of the poop. 0:17:24.080 --> 0:17:26.560 When I take my dog out on a walk, it's disgusting. 0:17:26.640 --> 0:17:29.560 Other people's dogs leave their poop on the sidewalk wherever, 0:17:29.640 --> 0:17:31.320 and he wants to go to all of it. And 0:17:31.440 --> 0:17:33.600 if you try to pull him away, like no, Charlie, 0:17:33.680 --> 0:17:35.720 you don't want to get into that, He's like no, no, 0:17:35.880 --> 0:17:39.800 I need to. Well, there's information there. There's there's information 0:17:39.880 --> 0:17:42.520 on a level that that that humans can barely grass. 0:17:42.560 --> 0:17:44.440 We just know it doesn't smell pleasant, or it certainly 0:17:44.520 --> 0:17:48.680 Lena doesn't look pleasant, but this is important environmental information 0:17:48.840 --> 0:17:51.280 to the dog, right right. So to take us back 0:17:51.320 --> 0:17:53.920 to the paper, then the idea is that while we 0:17:54.080 --> 0:17:58.119 are pooping, we're producing smells that advertise our vulnerability to 0:17:58.200 --> 0:18:01.959 potential predators exactly. And the full conclusion from the from 0:18:02.000 --> 0:18:04.399 the paper I think is rather great. They say, quote, 0:18:04.440 --> 0:18:08.720 we hypothesize that the voluntary control of defecation by our ancestors, 0:18:09.200 --> 0:18:12.680 together with greater brain volume, erect stature, opposable thumbs, and 0:18:12.800 --> 0:18:16.000 other changes, may have contributed to the successful march of 0:18:16.080 --> 0:18:19.840 hominids along the road of evolution. In fact, by deciding when, 0:18:20.160 --> 0:18:23.359 how and where to defecate may have several advantages in 0:18:23.400 --> 0:18:27.280 the complex prey predator relationship because spores are left in 0:18:27.359 --> 0:18:30.480 places undetectable by predators, or there are no fecal tracks 0:18:30.720 --> 0:18:36.840 who sent maybe easily individualated by prey genius. So we've 0:18:37.080 --> 0:18:40.440 we figured out evolutionarily speaking, that you need to know 0:18:40.800 --> 0:18:43.920 when to poop, because if you just poop anytime, you 0:18:44.000 --> 0:18:47.800 may be squandering opportunities or putting yourself in danger exactly. 0:18:48.320 --> 0:18:53.359 So let's break down how that actually functions biologically, though, Like, 0:18:53.480 --> 0:18:57.560 what is the actual biology of pooping. Okay, So the 0:18:57.600 --> 0:19:00.560 first step is six to eight times a day a 0:19:00.680 --> 0:19:05.720 peristaltic muscle contraction, called a mass movement, squeezes the contents 0:19:05.800 --> 0:19:09.359 of the colon along the path. Yeah, and peristalsis is 0:19:09.480 --> 0:19:13.440 the word for a wave of muscle contraction and relaxation 0:19:13.560 --> 0:19:17.240 that travels down the length of a tube inside the body. So, 0:19:17.400 --> 0:19:19.680 if you've ever run your fingers down the length of 0:19:19.720 --> 0:19:23.000 a sausage casing to squeeze the sausage out, or if 0:19:23.040 --> 0:19:25.520 you've ever tried to push the last bits of icing 0:19:25.600 --> 0:19:29.320 out of a piping bag, you have roughly simulated peristalsis 0:19:29.440 --> 0:19:31.320 on that on that tube. I want to say, this 0:19:31.440 --> 0:19:34.679 is also akin to how an earthworm moves, right, It's 0:19:34.720 --> 0:19:38.760 kind of this. Uh. This wave a wave of muscle 0:19:38.840 --> 0:19:42.240 contraction running down the length of of a cylindrical object, 0:19:42.320 --> 0:19:44.679 And in the sense of a hollow tube, that cylindrical 0:19:44.800 --> 0:19:49.119 object has its contents continually pushed down the length of it. 0:19:50.320 --> 0:19:53.399 So what happens next. The material pushes against the rectum 0:19:53.440 --> 0:19:57.560 wall with enough pressure to trigger the stretch receptors, and 0:19:57.640 --> 0:20:01.720 this triggers the defication reflects now. This entails a simultaneous 0:20:01.760 --> 0:20:05.480 contraction of the rectal wall muscles and a relaxation of 0:20:05.560 --> 0:20:09.440 the anal sphincter. Little known fact people actually have. I 0:20:09.520 --> 0:20:13.040 had no idea until last night. Two anal sphincters. Did 0:20:13.080 --> 0:20:15.000 you know you have to? No? No, I just thought 0:20:15.040 --> 0:20:17.480 there was the one. No, You've got to The internal 0:20:17.600 --> 0:20:21.879 anal sphincter is involuntary, so it holds up everything until 0:20:21.960 --> 0:20:25.280 a certain threshold of rectal wall stretching is reached, at 0:20:25.320 --> 0:20:28.440 which point it automatically says, okay, time to open the gate. 0:20:28.960 --> 0:20:31.639 But then you've still got the external anal sphincter. And 0:20:31.760 --> 0:20:35.720 this is what's under conscious executive control, perhaps for the 0:20:36.160 --> 0:20:39.040 reasons hypothesized by the researchers we were just talking about. 0:20:39.160 --> 0:20:41.639 It's like in a submarine movie when they're gonna launch 0:20:41.720 --> 0:20:44.520 a nuclear missile. Yeah, you have to have like both 0:20:44.680 --> 0:20:47.240 the key individuals push the button at the same time 0:20:47.920 --> 0:20:51.239 because otherwise there will be disastrous consequence. Right, I've got 0:20:51.320 --> 0:20:54.640 the missile key. Al right. So yeah, this is where 0:20:54.720 --> 0:20:57.560 human choice enters the picture. Uh A, poop your own 0:20:57.560 --> 0:21:01.040 adventure book, if you will, So you might choose to 0:21:01.200 --> 0:21:04.520 bear down, and this will raise the pressure on the 0:21:04.560 --> 0:21:09.359 rectum walls to prematurely trigger deification. So this is again 0:21:09.440 --> 0:21:11.440 part of the choice. It's not only the idea of 0:21:11.520 --> 0:21:14.399 the well I'm not getting ready to go yet inner sphincter. 0:21:14.720 --> 0:21:17.600 I'm going to go seek a spot behind a bush. 0:21:17.880 --> 0:21:20.720 You can also say, actually, I'm ready now, let's go 0:21:20.800 --> 0:21:25.440 ahead and expedite this process. But again, likewise you can 0:21:25.560 --> 0:21:28.639 hold it back. But the larger and more liquid the load, 0:21:28.920 --> 0:21:33.240 the harder this is. Roacha quotes so one gut expert 0:21:33.320 --> 0:21:36.760 in gulp as saying, quote, not even the sphincter of 0:21:36.880 --> 0:21:41.399 Hercules can hold back water. I just I like that 0:21:41.640 --> 0:21:46.000 by the sphincter of Hercules. I like the idea that 0:21:46.320 --> 0:21:49.520 since Hercules is very strong, like he's got big muscles 0:21:49.600 --> 0:21:51.920 on his arms and legs and back, he must also 0:21:52.040 --> 0:21:55.120 have an especially strong sphincter muscle. Of course he would. 0:21:55.119 --> 0:21:57.360 I mean, just if you have the blood of God's 0:21:57.760 --> 0:22:00.920 running through your body, if you're a hybrid of of 0:22:01.119 --> 0:22:04.560 humanity and deity, like, why would the why would the 0:22:04.560 --> 0:22:07.840