> It seems the list of animals that menstruate is quite short: humans, apes, monkeys, bats and elephant shrews. What do these seemingly disparate animals have in common?
My unfixed female dogs have periods. So either the article is poorly written, or they are ignoring animals that don't fit the theory.
Thanks. If people really want the one-sentence version:
"One difference is that animals that have estrous cycles reabsorb the endometrium if conception does not occur during that cycle. Animals that have menstrual cycles shed the endometrium through menstruation instead."
This is discussed in the OP at some length. Alas, the grandparent comment is something of a middlebrow dismissal.
Well, if you're going to attempt to be pedantic about it, the word "bleeding" isn't exactly correct to begin with. The discharge is endometrial tissue, not blood.
Before calling names, let's look at the article in detail.
"Of course, I wasn't the only one: most women menstruate. But most other female animals don't bleed outwardly like us. Even among those that give birth to live young as we do, only a handful of species menstruate."
So the term menstruate is used to mean to "bleed outwardly like us".
"If the woman doesn't get pregnant, progesterone levels begin to fall. The thick endometrial tissue with its blood vessels then begins to slough off, and passes out through the vagina. This bleeding is menstruation."
So they are expanding on the term menstruate. Now it's both "bleed outwardly like us" and "The thick endometrial tissue with its blood vessels then begins to slough off, and passes out through the vagina"
"On average, women lose 30 to 90 ml of fluid over 3-7 days of menstruation. We know, because scientists have given women pre-weighed pads and tampons, and weighed them again after use."
Clarifying the term menstruate and showing how to measure it. I'm going to paraphrase the definition of the term. So at this point, when they talk about menstruation, they are talking about a blood like fluid, that can be measured, and that happens when the the tissue and blood vessels pass out of the vagina.
The article has a break to talk about the history, theories, and research that has happened over the years. After that they get to the main point. "To figure out the truth, we need to compare animals that do and don't menstruate."
"Great apes do it too. Menstrual bleeding is easily detectable in chimpanzees and gibbons. However, gorillas and orang-utans bleed less copiously, so menstruation is only visible on closer inspection. Other primates, such as tarsiers, may also menstruate, but there is little hard evidence."
They re-iterate key parts of the term. When this article talks about menstruation, they are specifically talking about detectable bleeding.
Now we can get to the heart of my objection. They spent most of the article defining their usage of the term menstruation, and how it relates to the research.
The article claims "It seems the list of animals that menstruate is quite short: humans, apes, monkeys, bats and elephant shrews. What do these seemingly disparate animals have in common?", remember the definition they use for menstruate, blood and tissue passing though the vagina.
If you've ever owned an unfix female dog during heat, you'll be quite aware that they do, in fact bleed out their vagina for a period of time during their reproductive cycle. This fits with their definition.
The only mention of dogs is: "In dogs and cats, the foetuses dig in a little more. But in humans and other primates, a foetus will dig through all the womb lining to directly bathe in its mother's blood." This does not specify why dogs do not fit into their term. In fact this seems to support that dogs have a very similar cycle to humans.
So my question remains, Why are dogs excluded? They never acknowledge the contradiction. So either the article incorrectly sets up the terms, or they don't want to talk about dogs because it doesn't fit the narrative.
Look, your quibble isn't with me; it's with the biologists and the terms they've chosen to use for the different (and they are different) physiological phenomena. I'm using their terms here, in the ways they've defined them.
If you're utterly convinced that estrous and menstruation are the same, on the basis of some blood-like discharge occurring in both, then you might want to explore a career in academia. I'm sure there's a journal somewhere that would take your well-reasoned and compelling thesis on the subject. (You might need to pay them for the privilege, but as assiduously as you're defending your position here, that doesn't seem too unreasonable.)
Downvoted but you have a point. Why is there no moderation with regards to topical content on HN? Why should HN be a place for pop-sci articles and repostings from the likes of the Economist, LA Times, BBC, etc. r/startups has more content pertaining to - you know - actually starting a technology business than HN does. HN lately reads like newsclippings sent to me by my grandma.
Why is there no moderation with regards to topical content on HN?
As per the posted policy when I joined HN, this would have been topical. (It has changed since.) "Anything that would be interesting to hackers." I don't mind at all if the occasional pop-sci article comes by, so long as they don't all do so unfiltered.
Ironically, this comment and the one it replies to are distinctly against the moderation policy, as per my understanding.
Once upon a time, we weren't supposed to downvote to disagree. Then there was a capitulation, IIRC, and that became kosher. Now, I think things may be back to where we started. I don't keep miniscule track of changes to the moderation policy. (Maybe I should?)
You should understand that "my mom" and "my grandmother" are commonly used to denote technical illiteracy/incompetence and inability to keep up with the latest technological advances. This usage remans an unchallenged bastion of both sexism AND ageism -- a double whammy!
Proper usage:
* This app is so easy, my mom could use it!
* This article is easy to follow and avoids too much jargon -- my grandma would even understand most of it!
What you call "off topic" has been very much on topic for HN for a long time. The guidelines clearly say what is on topic, and it's more than "start up stuff".
> On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
That sentence has been in their since, well, ages.
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
Off-Topic: Most stories about politics, or crime, or sports, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic.
What we know for sure: foetuses produce hormones to keep the endometrial tissue from thinning. Once a zygote has implanted, the mother's hormones are thus no longer in control of whether her uterus will support its growth or not. Menstruation, when it happens, forcefully cleans out implanted zygotes, returning the uterine hormonal balance to normal.
What we guess that that implies: menstruation is a side-effect of enabling spontaneous abortion (miscarriage) of a still-live foetus, thus allowing females of those species to not have to go through the "avoid males you're not interested in during estrus" dance that most animals do. This confers social advantages.
In humans specifically, estrus is hidden completely from both male and female awareness. This confers further social advantages, but only could have evolved to fixation if the sexual-selection advantage of applying a "proximity during estrus" filter was completely outmoded/obviated by miscarriage.
Agree. I've seen ability to orgasm linked to selectivity for fertilization, as the speculation (I don't follow it enough to know if it is a theory or not in any allowable sense of the word) is that (female) orgasm during intercourse helps the sperm reach the egg.
It doesn't have to be "at will", our bodies do a lot of processing without us being consciously aware of it. I think it is well within reason that the body may detect an abnormal embryo and respond to it.
It's not in the control of the conscious mind. It is controlled by the body (or, you might say, by an evolutionary adaptation instantiated in the linkages of hormonal pathways in the brain.)
Note that miscarriage and spontaneous abortion are separate things. Miscarriage happens because the foetus dies in the womb, or the womb is ruptured, and the mother's body detects this. Any other cause is spontaneous abortion—effectively "something the mother['s body] did."
In humans, at least the experience of the emotions of extreme stress, and extreme fear, can cause spontaneous abortion. In a number of other animals (with a large subset of those being the ones that menstruate), there is the Bruce effect[1]: when the detection by the vomeronasal organ of an unfamiliar male's pheromonal signature precedes/causes spontaneous abortion.
That is a poor explanation given that extreme stress is known to have all sorts of physiological effects and is noted to negatively effect reproductive success in numerous species. But not all those species menstruate as noted by the article.
The thing muddying the water with stress, is that most things that trigger stress are also bad for the body, and thus for foetal development. Making rats run until they collapse from exhaustion might cause miscarriage, but it's unclear whether that is due to stress-hormone-induced spontaneous abortion, or due to the mother's body using up some micronutrient necessary for the foetus, thus causing a developmental defect which either kills the foetus or stalls its metabolism enough to be detected.
I'm unaware of whether there has been the study of the effects of purely psychological (or synthetic, using injected epinephrine) stress on spontaneous abortion rates.
It's much clearer with fear, though; things that cause a fear response don't tend to harm you (in fact, in an adaptive environment, to the degree that a fear response is created, you tend to avoid harm you would otherwise succumb to) but do trigger spontaneous abortion anyway. This would be much simpler to prove/disprove a purely-hormonal effect.
I suspect it's more a matter of ejecting poorly implanted zygotes—implanted enough to get some nutrients, but not enough to overtake the mother's hormonal balance. A poor implant could grow for a period of time before ultimately failing, fomenting a much more dangerous (for the mother) situation later in the term.
Since I moved to Missouri, I've been upset by a similar grammatical error: quotation marks used for emphasis. You would expect, say, all-capitals or an underline or italics, but you instead see 'Come taste the "best" burger in Missouri,' which is awful.
In New York, where I grew up, that use of quotation marks is called "scare quotes": quotation marks in all cases signal that you're detaching a text fragment from its context; with scare quotes you detach a phrase which reads just fine in that context to either bring focus to the phrase (like when you're defining it) or to indicate that the phrase itself is somehow problematic (like when you want to criticize the phrase, e.g. 'these "businessmen" are stealing our money,' where you're implying that they are either not truly men or not truly doing business per se.)
When you say that you have 'the "best" burger', to me it sounds like you're implicitly adding at the end, 'well, at least, it's the best at being an awful burger.'
This is a common practice in signs. It's wrong in literary English, but is it wrong in signs?
My pet theory is that quotes for emphasis were popularized in 20th century movie posters, where it was common to surround the movie title in quotations (this is still the accepted citation style in, say MLA style). This is probably wrong, of course.
Italics or bold for emphasis can be hard to hand-write, and the quotation marks for emphasis probably look more legible on chalk signs.
Is it sad? Who cares? This minor mistake almost never makes a meaning unclear and at best it's used as a social indicator to classify people (perhaps in some contexts people are using it deliberately for this reason).
Apostrophe's represent plural's in one of the languages most closely related to English, i.e. this has changed in the recent past, and will change again.
"It's" for "it has" is much more common in spoken English than written (even moreso than is explained by the fact that contractions are generally avoided in formal writing.)
Apostrophes are commonly used for plurals in signs, in what has come to be called the "greengrocer's apostrophe". It was a standard in the 19th century that has come to be disfavored in literary English.
https://en.wikipedia.org/wiki/Apostrophe#Greengrocers.27_apo...
I'm more curious as to whether the original article was published with an apostrophe, or the HN poster actually typed the title out from memory rather than cut/paste.
We do something similar in software development. If our program experiences a segfault, we usually let it die, instead of figuring out at runtime what went wrong and trying to do what we still can do. Then we change something and try again.
Making it hard for the embryo in the beginning and starting over if it didn't make it, is the biological equivalent to that strategy.
It might result in a heuristic whether it's worth investing more resources in it. Saving resources gives an evolutionary advantage.
On the other hand, it makes evolutionary progress harder since more conformity of the embryo is a condition to survive.
"Some species, such as domestic dogs, experience small amounts of vaginal bleeding while in heat; this discharge has a different physiologic cause than menstruation."
And if we talk about "periods" (like in the article title) and not just "bleeding," the fertility "periods" are everywhere.
Most animals do have fertility "periods" they just don't bleed. But again, we are primates, and a lot of primates do have the same menstruation that the humans have. So humans certainly aren't special in that aspect.
So you agree that most animals don't menstruate... what's wrong with the article's title?
EDIT: Oh, I think I get it now. "Period" in this context does not refer to the general fertility cycle. It is specifically a euphemism for menstruation. That is why you'll hear people saying things like "I'm on my period", "my period started late/early", etc. These phrases would not make sense if it referred to the fertility cycle in general, since from puberty to menopause, most healthy women are in some phase of a fertility cycle.
Yes, and even if the topic is just bleeding, humans aren't special, so it still shouldn't be "why do women bleed" but "why just primates, bats and one kind of shrew bleed during estrous cycle." Humans simply aren't special in that regard. And the whole "mystery" doesn't appear so dramatic anymore. It becomes obvious that that "optimization" developed more than once.
67 comments
[ 2.7 ms ] story [ 157 ms ] threadMy unfixed female dogs have periods. So either the article is poorly written, or they are ignoring animals that don't fit the theory.
The headline is (extra apostrophe), so I'd assume the article is too. :)
https://en.wikipedia.org/wiki/Estrous_cycle - note specifically #Differences_from_the_menstrual_cycle
"One difference is that animals that have estrous cycles reabsorb the endometrium if conception does not occur during that cycle. Animals that have menstrual cycles shed the endometrium through menstruation instead."
This is discussed in the OP at some length. Alas, the grandparent comment is something of a middlebrow dismissal.
"Of course, I wasn't the only one: most women menstruate. But most other female animals don't bleed outwardly like us. Even among those that give birth to live young as we do, only a handful of species menstruate."
So the term menstruate is used to mean to "bleed outwardly like us".
"If the woman doesn't get pregnant, progesterone levels begin to fall. The thick endometrial tissue with its blood vessels then begins to slough off, and passes out through the vagina. This bleeding is menstruation."
So they are expanding on the term menstruate. Now it's both "bleed outwardly like us" and "The thick endometrial tissue with its blood vessels then begins to slough off, and passes out through the vagina"
"On average, women lose 30 to 90 ml of fluid over 3-7 days of menstruation. We know, because scientists have given women pre-weighed pads and tampons, and weighed them again after use."
Clarifying the term menstruate and showing how to measure it. I'm going to paraphrase the definition of the term. So at this point, when they talk about menstruation, they are talking about a blood like fluid, that can be measured, and that happens when the the tissue and blood vessels pass out of the vagina.
The article has a break to talk about the history, theories, and research that has happened over the years. After that they get to the main point. "To figure out the truth, we need to compare animals that do and don't menstruate."
"Great apes do it too. Menstrual bleeding is easily detectable in chimpanzees and gibbons. However, gorillas and orang-utans bleed less copiously, so menstruation is only visible on closer inspection. Other primates, such as tarsiers, may also menstruate, but there is little hard evidence."
They re-iterate key parts of the term. When this article talks about menstruation, they are specifically talking about detectable bleeding.
Now we can get to the heart of my objection. They spent most of the article defining their usage of the term menstruation, and how it relates to the research.
The article claims "It seems the list of animals that menstruate is quite short: humans, apes, monkeys, bats and elephant shrews. What do these seemingly disparate animals have in common?", remember the definition they use for menstruate, blood and tissue passing though the vagina.
If you've ever owned an unfix female dog during heat, you'll be quite aware that they do, in fact bleed out their vagina for a period of time during their reproductive cycle. This fits with their definition.
The only mention of dogs is: "In dogs and cats, the foetuses dig in a little more. But in humans and other primates, a foetus will dig through all the womb lining to directly bathe in its mother's blood." This does not specify why dogs do not fit into their term. In fact this seems to support that dogs have a very similar cycle to humans.
So my question remains, Why are dogs excluded? They never acknowledge the contradiction. So either the article incorrectly sets up the terms, or they don't want to talk about dogs because it doesn't fit the narrative.
If you're utterly convinced that estrous and menstruation are the same, on the basis of some blood-like discharge occurring in both, then you might want to explore a career in academia. I'm sure there's a journal somewhere that would take your well-reasoned and compelling thesis on the subject. (You might need to pay them for the privilege, but as assiduously as you're defending your position here, that doesn't seem too unreasonable.)
You've completely missed my point.
I am, therefore, a little confused over the article.
As per the posted policy when I joined HN, this would have been topical. (It has changed since.) "Anything that would be interesting to hackers." I don't mind at all if the occasional pop-sci article comes by, so long as they don't all do so unfiltered.
Ironically, this comment and the one it replies to are distinctly against the moderation policy, as per my understanding.
How? I don't recall any change. Or are you referring to Startup News, the predecessor of HN?
Proper usage:
* This app is so easy, my mom could use it!
* This article is easy to follow and avoids too much jargon -- my grandma would even understand most of it!
... you get the picture.
> HN lately reads like newsclippings sent to me by my grandma
which continues to propagate the insidious, ageist and sexist assertion that older women don't get high technology.
https://news.ycombinator.com/hackernews.html
Of course we do moderate topical content on HN. But an article on the history of hypotheses about menstruation is hardly topical.
What you call "off topic" has been very much on topic for HN for a long time. The guidelines clearly say what is on topic, and it's more than "start up stuff".
https://news.ycombinator.com/newsguidelines.html
> On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
That sentence has been in their since, well, ages.
https://web.archive.org/web/20080616133301/http://ycombinato...
On-Topic: Anything that good hackers would find interesting. That includes more than hacking and startups. If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.
Off-Topic: Most stories about politics, or crime, or sports, unless they're evidence of some interesting new phenomenon. Videos of pratfalls or disasters, or cute animal pictures. If they'd cover it on TV news, it's probably off-topic.
What we know for sure: foetuses produce hormones to keep the endometrial tissue from thinning. Once a zygote has implanted, the mother's hormones are thus no longer in control of whether her uterus will support its growth or not. Menstruation, when it happens, forcefully cleans out implanted zygotes, returning the uterine hormonal balance to normal.
What we guess that that implies: menstruation is a side-effect of enabling spontaneous abortion (miscarriage) of a still-live foetus, thus allowing females of those species to not have to go through the "avoid males you're not interested in during estrus" dance that most animals do. This confers social advantages.
In humans specifically, estrus is hidden completely from both male and female awareness. This confers further social advantages, but only could have evolved to fixation if the sexual-selection advantage of applying a "proximity during estrus" filter was completely outmoded/obviated by miscarriage.
A garbled version of that theory got some politicians in hot water with the whole "during rape, their body can shut it down" comment.
Note that miscarriage and spontaneous abortion are separate things. Miscarriage happens because the foetus dies in the womb, or the womb is ruptured, and the mother's body detects this. Any other cause is spontaneous abortion—effectively "something the mother['s body] did."
In humans, at least the experience of the emotions of extreme stress, and extreme fear, can cause spontaneous abortion. In a number of other animals (with a large subset of those being the ones that menstruate), there is the Bruce effect[1]: when the detection by the vomeronasal organ of an unfamiliar male's pheromonal signature precedes/causes spontaneous abortion.
[1] http://en.wikipedia.org/wiki/Bruce_effect
I'm unaware of whether there has been the study of the effects of purely psychological (or synthetic, using injected epinephrine) stress on spontaneous abortion rates.
It's much clearer with fear, though; things that cause a fear response don't tend to harm you (in fact, in an adaptive environment, to the degree that a fear response is created, you tend to avoid harm you would otherwise succumb to) but do trigger spontaneous abortion anyway. This would be much simpler to prove/disprove a purely-hormonal effect.
No.
This is not a tl;dr of the article, which proposes several scientific hypotheses, which do not include what you have said.
It mentions the case of spontaneous abortion being beneficial where the embryo is not likely to be viable or the foetus is causing harm to the mother.
To non-native speakers: apostrophes are for possession, not plural.
You could easily repeat that for plenty of native speakers. It's one of the most common mistakes in written English.
There's a bar that we drive past frequently that does it with everything.
They're "Now accepting application's" and their "Burger's are $2"
Sad.
In New York, where I grew up, that use of quotation marks is called "scare quotes": quotation marks in all cases signal that you're detaching a text fragment from its context; with scare quotes you detach a phrase which reads just fine in that context to either bring focus to the phrase (like when you're defining it) or to indicate that the phrase itself is somehow problematic (like when you want to criticize the phrase, e.g. 'these "businessmen" are stealing our money,' where you're implying that they are either not truly men or not truly doing business per se.)
When you say that you have 'the "best" burger', to me it sounds like you're implicitly adding at the end, 'well, at least, it's the best at being an awful burger.'
The auther started the blog while at the University of Georgia, so the problem isn't confined to Missouri.
My pet theory is that quotes for emphasis were popularized in 20th century movie posters, where it was common to surround the movie title in quotations (this is still the accepted citation style in, say MLA style). This is probably wrong, of course.
Italics or bold for emphasis can be hard to hand-write, and the quotation marks for emphasis probably look more legible on chalk signs.
Apostrophe's represent plural's in one of the languages most closely related to English, i.e. this has changed in the recent past, and will change again.
Holy crap, really? I just figured it was because people were learning English on the internet. Also a peeve: "Loose" when the writer means "lose."
Not that I want to derail the board or anything...
It's not so easy.
it's = contraction of it is or it has
its = possessive form of it
"It's been a long time since we last met."
[0] http://www.bristol.ac.uk/arts/exercises/grammar/grammar_tuto...
But it is a real thing.
All sorts of theories in the article, none with any real evidence, except "this makes sense to me".
The mother actively tries to kill anything that might be in her uterus, she even periodically cleans her uterus radically by ejecting a layer of it.
The embryo needs to produce hormones that manipulate the mother to stop that, and deliver them into the mother.
If the embryo fails, it dies.
Source: http://aeon.co/magazine/science/pregnancy-is-a-battleground-...
We do something similar in software development. If our program experiences a segfault, we usually let it die, instead of figuring out at runtime what went wrong and trying to do what we still can do. Then we change something and try again.
Making it hard for the embryo in the beginning and starting over if it didn't make it, is the biological equivalent to that strategy.
It might result in a heuristic whether it's worth investing more resources in it. Saving resources gives an evolutionary advantage.
On the other hand, it makes evolutionary progress harder since more conformity of the embryo is a condition to survive.
https://answers.yahoo.com/question/index?qid=20060612224917A...
It's however not "the same" as the one in primates:
http://en.wikipedia.org/wiki/Menstruation_%28mammal%29
"Some species, such as domestic dogs, experience small amounts of vaginal bleeding while in heat; this discharge has a different physiologic cause than menstruation."
And if we talk about "periods" (like in the article title) and not just "bleeding," the fertility "periods" are everywhere.
http://en.wikipedia.org/wiki/Spawn_%28biology%29
Even corals have spawn cycles.
Most animals do have fertility "periods" they just don't bleed. But again, we are primates, and a lot of primates do have the same menstruation that the humans have. So humans certainly aren't special in that aspect.
EDIT: Oh, I think I get it now. "Period" in this context does not refer to the general fertility cycle. It is specifically a euphemism for menstruation. That is why you'll hear people saying things like "I'm on my period", "my period started late/early", etc. These phrases would not make sense if it referred to the fertility cycle in general, since from puberty to menopause, most healthy women are in some phase of a fertility cycle.