Because they mostly have some kind of visible ovulation (except for a few monkeys), puberty is obvious.
What I meant by prominent is just that they became more visible more of the time. Anytime a human is face-to-face with a human female (and we primarily interact face to face) then the boobs are facing also.
I mentioned skin elasticity as a bonus feature if you will. But it’s not so far-fetched: look at the difference that wrinkles make; we are highly tuned to noticing subtle signals of ageing.
Meanwhile one bodypart mimicking another body part…any examples of that in nature? I can only think of some species that have a fake head so predators attack the wrong thing, not in sexual selection. What bodypart is the gelada supposed to mimick, I’m coming up blank.
As I mentioned, most species primarily signal that they are in heat, not passed puberty per se. But human females do not go on heat. The only things that can be signalled are “I’m female”, “I’m healthy” and “I have (mostly) completed puberty”.
As I mentioned above, the female gelada has a heart-shaped “necklace” of blisters around her genitalia that mirrors a similar set on her chest. There’s really no obvious evolutionary purpose or advantage to this, but it is precisely a functional analogue for the suggestion that breasts are a buttocks mimic.
There are other examples in the primate world. The male mandrill’s brightly colored red and blue face markings mimic those on his genitals. I submit that the prominent nose on the proboscis monkey is a penis mimic.
From Morris, The Naked Ape, p. 71
Morris isn’t the only one supporting this, but he’s the easiest to find. I’ve been looking for another source I found that shows drawings of the gelada female markings, but haven’t been able to find it. Most internet sources write about the patterns on the chest, but ignore the one around the genitals.
Yeah those couple of species are interesting, but very obviously there are vast numbers of species that have features chosen by sexual selection that don’t resemble any other parts of the body.
You think it’s more plausible that breasts have evolved to resemble the buttocks, I find it more plausible they are just a sign of sexual dimophism and development, but either way it seems we agree that sexual selection was likely the driving force in why humans’ boobs got so big. I think that’s as far as we’re going to get here, it’s not like there is a scientific consensus on their evolutionary pathway.
The gelada doesn’t seem at all comparable. In the gelada, the markings on both the chest and the pubic area both serve purely and only as a sexual marker. The female gelada has a sexual marker, and she displays it on two different parts of her body. Since it’s purely a marker in both places, it’s equally plausible that it’s the pubic marker mimicking the chest one, or that both arose at the same time.
In humans, enlarged female breasts are almost certainly a sexual marker, but enlarged buttocks are not: We know why we have enlarged buttocks. It’s because they’re necessary to accommodate our upright gait and our large heads at birth.
Is there any known species that has a sexual marker in mimicry of some other, functional part?
As I mentioned, in “Why Is Sex Fun” Diamond specifically points out - humans have evolved hidden ovulation. This is one reproductive strategy that keeps the male around to help feed his offspring, while he hopes to create more offspring. The human female is notably one of the only species that maintains full-ish breasts (YMMV) and the logical assumption is that this is a sort of signal that she is capable to reproduce. Breasts being present only after puberty, and also they are notoriously less “fullsome”(?) and that they sag more with age is probably additional evidence that they are for signaling sexual readiness and reproductive vigor as well as for breastfeeding. It is as much or more than the wide hips a signal that the body is capable of giving birth. There have been plenty of studies that show that both characteristics appeal to males.
The idea that “breasts mimic buttocks” seems like one of those “just so (sex) stories”, much like the Electra-Oedipus BS that Freud made up to hide the evidence he found of childhood sexual molestation.
The hypothesis fails to mention then why it would evolve - which came first, the missionary position or the faux butt? IMHO the missionary position as it evolved was a means to reinforce the emotional bond that sex tends to create, which again provides impetus for the male to stick around and keep providing in order to get provided for.
(Note too, that humans being one of the only species walking upright, evolved those large buttocks muscle groups and so is the only animal that need to wipe its ass.)
The missionary position didn’t “evolve”. Humans have sex in every which way we can, and the missionary position is only one of those many, many ways. Any explanation that’s based on “because humans have sex face-to-face” is laughable right from the start.
That can’t be literally true. Our ancestors 100 million years ago did not mate that way.
Our ancestors probably didn’t do the wheelbarrow either.
There are lots of physical actions that humans didn’t or couldn’t do, and then one day did. The vast majority didn’t “evolve” they were just a biproduct of other changes, or needed to be learned.
That said, I think it’s possible that some relevant changes occurred, I’m just saying it’s speculative and there’s no reason to assume that happened.
From the shape and location of the vagina, it seems a rear mounting was the primary method of intercourse at one time, but as we became more bipedal there may have been a selection pressure to also be able to comfortably copulate from a face to face position.
You’re joking, right?
The nose of a male proboscis monkey looks nothing like its penis. Which is never flaccid, bright red, pointy, and with a black scrotum, and looks nothing like the nose.
The missionary position (“Oh God! Ohhh…God!”) is a side effect of human hip configuration, which in turn is a result of evolving the ability to walk easily on two legs. That we retain the ability to do it monkey-style is a benefit; that we enjoy sex enough to find other creative ways is a tribute to the evolutionary strategy that developed pleasure as a motivator for reproduction. (and the big brain that we put to other uses besides tool-making and strategic hunting)
But face-to-face it seems to me also developed the stronger emotional bond that also encourages the male to stick around (and the couple to stick together, literally as well as figuratively) which is a benefit in evolutionary terms.
But that’s still assuming that face-to-face is the “normal” or “default” human sexual position. If that were the case, then we wouldn’t call it “the missionary position”; we’d just call it “the position”. The whole reason it’s called the “missionary position” is because, allegedly, most humans in most parts of the world mostly didn’t use that position, until educated by Europeans.
And is there any evidence, say, that couples who have missionary-position sex stay together for longer than couples who use other sexual positions?
There are, for example, old illustrations (India and Pompeii come to mind) that show assorted positions which involve face-to-face, so this particular configuration is not a protestant invention. (“Lie back and think of England!”) IIRC the “missionary position” expression came from Polynesia where the predominant position was spooning, also not a common animal kingdom position.
But very good points - I suppose deeper research is called for, using the full resources of the internet.
Oh, sure, the Missionary Position wasn’t actually exclusive to the missionaries: That’s why I included the “allegedly”. But neither is it the default position that most humans use.
What is the “default position”? (asking for a friend)
Does anyone propose that explanation? I’ve always heard it as simply face to face interaction ie talking to one another etc.
See Kama Sutra, Part 2, Chapter VI.
Both of these comments show the problem with humans commenting on human behaviour - it’s hard to be objective especially with a Judeo-Christan outlook which takes the line that people are a totally different thing to animals.
The author of the quote that TokyoBayer relates doesn’t seem able to face the fact that the human animal may well have physical and mental features that don’t fit with their views on gender relations. The reality is that there are species where one sex bites the other’s head off after mating. Many species involve the males physically fighting amongst themselves for the privilege of raping the female. Many species have features (smells, visual features) that unquestionably exist to attract a mate.
Morris may be right or wrong in the details (or altogether) but the fact that his theories can be rejected by someone on the basis they are “disrespectful” of one sex shows how hard it is to discuss this stuff objectively.
And Musicat, your comment shows the same problem. Why would a zoologist not be qualified? Would you have said the same thing if Morris proposed a theory about horse mate selection etc? Or monkeys? So why not humans?
It’s been many years since I read Desmond Morris, so my memory of details and particulars has faded, and I don’t have any of his books in my library to check.
What I do remember is my reaction to many of his claims – and that’s all many were, claims. They reminded me of “pet psychiatrists” or “animal psychics” who purport to explain why your pet does something, like bark too much, jump on the couch, or retrieve a toy. They often claim that they can tell what’s in a pet’s mind. “Fido loves you very much, that’s why he likes to squeeze the toy.”
While they may be right, without proof, it’s little more than fantasy, projecting human emotions on a different species. Morris’ claims, as logical as he makes them sound, to me, don’t have anything solid behind them.