I'm having fun reading about penises today. I've learned that when men are timed, sexual intercourse lasts between 2 and 40 minutes, with an average of just over 7 minutes. Not to worry, chimpanzees only have sex for 8 seconds and gorillas for one minute. Why is that? Well, suggests the author, animals have to move fast or they'll be eaten. Apparently nature and evolution are lined up against us women. Wham-bam-thank-you-ma'am is in our genes.
This is a pretty common view. Except it's missing something. Chimpanzees don't have sex for 8 seconds and stop. They go into heat and screw every male in sight for six days. Female chimps have been known to have sex 20 times in one day, although the daily average is only 6. Then again, they may have sex every 10 minutes for half the morning.
Male chimps, meanwhile, fight each other for as many turns as they can get. Luckily, they're able to get it up again after five mintues.
Coming fast probably isn't about avoiding predators at all. Maybe a chimpanzee comes fast because he needs to get his sperm in before the next guy shows up. And saying sex only lasts 8 seconds is missing the big picture, at least for a female chimpanzee.
Gorillas are another story entirely. A dominant male keeps a harem of females. When they go into heat, he has sex with them. When he's not looking, they sneak off with other males. Once again, we don't need to look for predators to explain anything: the male gorilla is probably coming fast to avoid being attacked by another gorilla.
The facts about primate sex life are well known. We just forget them when they don't fit into our ideas about men and women.
Here's an alternative explanation of human evolution. As humans became more monogamous, the male didn't have to come as quickly as his primate relatives. The women didn't all belong to one polygamous male who would beat you up if you went near them. Nor did you have to fight the rest of your troop for your turn.
Still, in order to keep his woman faithful, the male human had to be able to keep her satisifed. He couldn't give her sex twenty times a day, but he didn't want her to go elsewhere. Men evolved large penises and the ability to last up to 40 minutes. Nature and evolution are working for women's pleasure, not against it. The 60-minute-man is in our genes.
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I'm not sure if I am reading this correctly, but I feel as though you are presenting the point that heterosexual women who have sex with a heterosexual man expect them to be able to last as long as possible, otherwise she is not satisfied. This does not take into consideration women who do not mind when they man comes quickly - an example would be me. I actually get tired and somewhat bored after about a half hour of sexy time; and this has happened with more than one guy so please don't assume that the guy I am with cannot please me. I just think that some people (men, women, or both) do not expect the guy to be able to last 40 mins in order to prove his worth as a good sexual partner.
Humans have sexual intercourse for much longer than our primate relatives. For women's preferences to have affected evolution, we would just need to want sexual intercourse to last more than one minute. A man who could last as long as his partner wanted might be better able to keep his mate faithful and/or have more partners.
I'm sure that most evolutionary biologists would agree with your main points.
Science can be misapplied in false support of prejudice and bigotry, but prejudice and bigotry can exist without science. Real science is always skeptical, always questioning, always demanding that ideas be tested. As such, science is among the most powerful tools we have for fighting prejudice and bigotry.
Are you talking about the common chimp, or the bonobo chimp? These two species have very different sexual habits. Bonobos use sexual acts for social reasons (e.g. bonding, resolving conflicts) more so than for procreation, whereas common chimps only engage in sexual activity when the females are in estrus.
I'm guessing you meant common chimps, because bonobos don't depend on estrus to have sex. It's not true that female common chimps "go into heat and screw every male in sight for six days." They've been observed to have preferences for who their partners are. Frequently, a female common chimp will mate with the male that spends a lot of time in proximity to her when she's not in estrus. I don't think they've ever been observed to mate totally indiscriminately.
Also, your description of gorilla mating is a bit off. When observed in the wild, male gorillas seem to have a low libido. The females may entice the male into sex by presenting their genitals, but more often than not, they have to initiate copulation by actually sitting on the male's penis. I'm pretty sure this is true of both mountain and lowland gorillas.
The facts about primate sex life are well known.
Not really. We have plenty of observations, but our interpretation of these observations is controversial and frequently changing. Until the past decade or so, tamarins were thought to be monogamous because they travel in pair groups, both sexes share in caring for their twin offspring, and males and females are about the same size. These are usually thought to be good indicators of monogamy. However, paternity testing and closer observation revealed that both males and females sneak off from their mates for extra-pair nookie. So, even with decades of research on tamarins, researchers originally came to the wrong conclusion about their mating habits.
Chimps and gorillas have been studied more closely than tamarins, but that doesn't mean we necessarily understand our observations or can apply them to human behavior.
The sexual behavior of primates is greatly diverse. Monogamous, polyandrous, polygynous and polygynandrous/promiscuous species of primate exist. Let's examine the apes for a moment. The bonobo chimp and the common chimp are both considered promiscuous, meaning that males and females take more than one sex partner. Gorillas are one-male polygynous (meaning that a non-silverback male is basically out of luck). Gibbons and siamangs are generally monogamous. Orangutans...in addition to commonplace forced matings (what some researchers are hesitant to call rape in non-humans), they display overlap-promiscuity, meaning that these solitary animals basically have sex when they run into each other.
I've never read any scientific literature on the length of copulation in relation to evolution, but I'll have to look into it. What I've always heard lauded as a good measure of monogamy vs. promiscuity is penis and testicle size. Large penises generally indicate promiscuous males, and large testicles generally indicate promiscuous females. Humans have both. On the other hand, relatively equal body size between males and females is usually a decent indicator of monogamy. Based on these three factors, humans appear to lie somewhere between promiscuity and monogamy.
I have never seen anything before suggesting that male promiscuity is related to penis size, perhaps because human penises are so much bigger than most other apes. Rather I've seen a kind of wonder that humans penises are so much larger with no real explanation.
Hmm. I know I've read a paper discussing human sexuality using comparisons to other primates, but I've yet to find it. I'll keep searching, but don't think I'm blowing off your last comment. You raise a good point - the human penis is rather large compared to other primates. It also isn't covered in spines, like practically every other primate's penises are. Perhaps that's another score for female sexual selection? :P
I've read that in general primates with larger penises are species with more promiscuity. The idea is that if a female has sex with more than one male in a short period of time, it becomes competitive in terms of whose sperm can get to her eggs first. So having a larger penis that injects more sperm with more force is an advantage there.
If there is complete monogamy, that doesn't matter.
I believe human penises are on the larger size of that scale, showing that there was some competition in those terms. There have also been studies showing that the ridge on the end of the penis works to scoop out any semen that is there from a previous partner.
So yeah, penis size/shape is related to promiscuity in general.
What I've read has been that species with larger testicles have more promiscuous females; the males need bigger testicles so that they can ejaculate more sperm. Chimpanzees have much larger testicles than humans because their sperm must compete with the sperm of many other males.
Humans may have to worry about female cheating, but we are nowhere near as promiscuous as chimpanzees or bonobos.
It seems my memory is shoddy. Penis length can indicate male promiscuity, but only in species in which the males engage in penile displays. Not so useful for most species. Pantheon is correct - penis length more often correlates with general promiscuity.
Yes, I was talking about the common chimp. Many of the observations about bonobos using sex for social interactions were made in zoos. Scientist who observe them in the wild say their sexual behavior is different there and bonobo nature is currently a subject of debate.
My point about female chimps is that they have sex with many different males in their troop (I think there aren't usually many other males in sight). While they sometimes show preferences, having sex with many different individuals seems to be the norm. Thus, a male might need to come quickly to fight off other males, not predators.
Your information on male gorillas not seeming interested in sex is fascinating. However, I think that female gorillas do have sex with males other than the dominant one when they can do so out of his sight. So those males might need to be very careful to come quickly and not get caught.
I have never seen anything relating monogamy to length of intercourse either. My main point is that our ideas about humans shape how we interpret the data we have on primate sex. The author of the book I read assumed that apes must be ejaculating quickly to avoid predators because we humans don't want to think of females cheating (gorillas) or having sex with lots of males (chimps).
In addition, popularizations of evolution tend not to look at monogamy as something males have to convince females to do, despite all the evidence in nature of females cheating. Our culture is way too wedded to the idea that women need to trick men into monogamy. Male humans really, really need to find a woman who will be faithful to them if they want to pass on their genes.
So it never seems to occur to anyone that, hmm, maybe men have bigger penises than other apes because women want them to. Or maybe they have to last longer so their lovers won't cheat.
Many of the observations about bonobos using sex for social interactions were made in zoos.
While I'm sure their sexual behavior in captivity may be exaggerated (either physically, or through interpretation by humans), wild bonobos do often engage in sexual activity for social reasons, a behavior not commonly seen in other primates. A quick Google scholar search reveals a number of recent studies on wild bonobo sexual behavior.
While they sometimes show preferences, having sex with many different individuals seems to be the norm. Thus, a male might need to come quickly to fight off other males, not predators.
That seems like a valid theory for chimpanzees. Both males and females have sex with multiple partners, and male chimps are very aggressive. Keeping intromission brief could potentially avoid conflicts with other males. It could also protect female promiscuity, by allowing her to engage in secret trysts without repercussions (woo, anthropomorphism galore in that sentence. Couldn't help myself).
However, I think that female gorillas do have sex with males other than the dominant one when they can do so out of his sight.
From what I was taught and read in the past, this happens infrequently. However, I cannot find any recent scholarly articles that say either way. Recent articles do refer to both lowland and mountain gorillas as polygynous though, leading me to believe that females rarely have more than one partner.
The author of the book I read assumed that apes must be ejaculating quickly to avoid predators because we humans don't want to think of females cheating (gorillas) or having sex with lots of males (chimps).
Hm. I'd never thought of that, but mostly because I'd never really heard the theory of predation influencing the length of copulation. In all the bio classes I took (particularly, sex & repro. of mammals), we discussed a variety of theories for each mating strategy. I'm sure predation came up at some point, but one theory was never really lauded over another. Assuming the predation/copulation theory is more common outside of my experience, I understand your point better. Avoiding males rather than predators makes sense, especially given that healthy adult gorillas or chimpanzees aren't generally the target of their predators.
popularizations of evolution tend not to look at monogamy as something males have to convince females to do
Yep, we just have uptight culture and old evolutionary theory to thank for those antiquated notions. :) Have you ever read Dr. Tatiana's Sex Advice to All Creation by Olivia Judson? The first two chapters, I believe, deal with the myth of the "chaste female." It's written in a humerous Q&A sex column format, where various creatures write to Dr. Tatiana for advice. If you can tolerate that sort of writing, you'd probably find the material enjoyable and informative.
Out of curious, what book did you read to get you thinking on this topic?
The book I was reading that set me off was "Size Matters." It's a book about penises and I basically like the book. I think I've seen the idea that animals come more quickly to avoid predators somewhere else and I didn't want to focus on the particular book. Popular interpretations of sociobiology are the real problem.
The idea that female chimps want to engage in "secret trysts" may not be that far off. A recent study found that female chimps make less noise during sex when they know that there are other males nearby who might hear and interrupt them. Although, on the other hand, many scientists think that female chimps want the males to know they've been promiscuous so none of them know whose baby it is and the males won't commit infanticide.
The New Yorker had an article recently about the controversy over bonobo behavior, if you are interested.
http://www.newyorker.com/reporting/2007/07/30/070730fa_fact_parker?curre
Thanks for the link. That was an interesting article, and it did make me reexamine what I'd posted. I'm hesitant to trust the media to report scientific findings accurately, but by limiting my previous Google scholar search to only the past 9 years, (keywords: "wild bonobo" + sex/mating/genital/copulation), it does seem like the evidence for highly sexual bonobos is a bit shaky. I think the most interesting part of the article, though, was the following:
When I asked Hohmann about the bonobo sex at Lui Kotal, he said, “It’s nothing that really strikes me.” Certainly, he and his team observe female “g-g rubbing,” which is not seen in chimpanzees, and needs to be explained. “But does it have anything to do with sex?” Hohmann asked. “Probably not. Of course, they use the genitals, but is it erotic behavior or a greeting gesture that is completely detached from sexual behavior?”
My previous comments about bonobos showing sexual behavior uncommon to most primates was partially based on the fact that they engage in g-g rubbing. I guess I just automatically or unconsciously assumed that involvement of genitals implies the act is sexual, rather than purely social. That assumption could very well be due to the puritanical culture I was brought up in.
I think the new research raises real questions about the way bonobo behavior has been presented in the past. However, I think there are still some interesting differences about bonobo sexuality. And even if some behaviors are only seen in captivity, the fact that they are is significant, since chimpanzees don't behave the same way in captivity. I left them out of my discussion of how fast males come, though, because of the controversy and because the book the irritated me didn't actually mention how long bonobos last.
I believe bonobos do not have sexual intercourse or any sexual contacts for very long compared to humans. The females also go into heat and mate with many different males. On the other hand, they have relatively large penises.
"I've learned that when men are timed, sexual intercourse lasts between 2 and 40 minutes, with an average of just over 7 minutes"
First of all...Stop doing that! Put the stopwatch away. It is NOT erotic.
Maybe a bit.
Unless she's wearing a lab coat and librarian glasses. A clipboard could be a plus. Am I right?
*crickets*
It all seems to make sense, except for what I know of the evolution of the clitoris seems to contradict this proposed skew in evolutionary biology towards the pleasure of the female.
I don't mean to be stating the obvious, but the short-term advantages of sex for males like myself is self-evident. The pleasure of sex is, for most of us, pretty easy to achieve. Ejaculation and orgasm go hand-in-hand.
Contrast that with the female experience. I obviously can't speak to personally, but many of the women that I have spoken to on the subject, as well as some things I've read, seem to indicate that an inability to achieve orgasm through penetration alone is fairly common (I feel like calling it a "problem" would be textbook male egotism) Even apart from that, pleasure from sex does not seem to be automatic in females as it is in males.
That presents a dilemma with this conception of evolutionary biology with regard to sex, doesn't it? There's a disparity there. As has been indicated earlier by maidensnowflake, that sexual longevity shouldn't mean much in this conception if the females aren't having much fun of it. It's not much of an "enticement" otherwise, right? The status of female sexual pleasure as being almost apart from sexual function as opposed to part and parcel of it as it is with males is something that always puzzled me. Perhaps someone can enlighten me? Am I totally off-base here?
I was reading along, nodding in agreement until I got to this:
The status of female sexual pleasure as being almost apart from sexual function as opposed to part and parcel of it as it is with males is something that always puzzled me.
I honestly am not sure what you're asking. Could you rephrase? I think it's the word "function" that I'm stuck on. Are you referring to the act of sex, or orgasm, or something else entirely?
I was careless with my wording, I apologize.
What I meant was that if you conceive of intercourse as having the primary purpose of procreation (personally I'm hesitant to think of such things in teleological terms for myriad reasons, but we have to when we think about it in terms of biology) then it's curious that, in the case of humans at least, sexual "success" requires orgasm on the part of males - no orgasm means no insemination means no fulfillment of purpose - but not on the part of females, who can get pregnant whether or not they experience pleasure from the act.
Wouldn't there be greater incentive to procreate if females took pleasure in the act with the same frequency as males? Is there an evolutionary explanation for this?
Just an aside, I guess.
Damn, my comment below was supposed to be a response to yours. -_-
"Wouldn't there be greater incentive to procreate if females took pleasure in the act with the same frequency as males? Is there an evolutionary explanation for this?"
There's an incentive to procreate with the males that are able to satisfy you, because females *can* take pleasure in the act with the same frequency as males, if just the male in question is able to learn about female sexuality, so there's a selection process going on.
"What I meant was that if you conceive of intercourse as having the primary purpose of procreation (personally I'm hesitant to think of such things in teleological terms for myriad reasons, but we have to when we think about it in terms of biology) then it's curious that, in the case of humans at least, sexual "success" requires orgasm on the part of males - no orgasm means no insemination means no fulfillment of purpose - but not on the part of females, who can get pregnant whether or not they experience pleasure from the act.
Wouldn't there be greater incentive to procreate if females took pleasure in the act with the same frequency as males? Is there an evolutionary explanation for this?"
Yes. If females (in the case of most species, sometimes it is the males) mated as indiscriminately as males they would probably be stuck with lower quality genes in their offspring than if they discriminated between the males.
Females can usually produce fewer offspring than can males and often invest more in offspring than do males so letting any old sperm meet their eggs is selected against.
Also, females are only fertile, ie ovulating, very occasionally which is normally connected to sexual arousal ie estrus. Species where females are interested in sex beyond estrus, and indeed where males are sexually interested in females beyond estrus, are having a lot of sex that cannot possibly lead to conception anyway.
But that does not mean it is not connected to reproductive fitness. Sarah Hrdy argues that female 'promiscuity' is to confuse paternity and avoid infanticide by males. Frans de Waal also considers that the 'promiscuity' in bonobos may have evolved to prevent infanticide by males.
Intercourse and orgasm and fertility are straightforwardly connected in males. In females it is more complex with only occasional fertility, the need for greater discrimination in mates, especially when actually fertile, and sex for females having other functions beyond sperm meeting egg ie obtaining food from males or protection from males of deflecting potential infanticide by males - things that all go towards the female's reproductive fitness.
Females who enjoy G-spot stimulation or other vaginal pleasure would generally want sexual intercourse to last longer. So I think females would prefer males who can last longer.
Biologists definitely wonder why the clitoris evolved when intercourse doesn't usually make women have orgasms. However:
1) the clitoris prepares women for intercourse and makes it much more pleasurable - the woman gets lubricated, her vagina enlarges, and the whole area around the vagina is swollen so that she can better sense penetration. (I'm not saying that's the only purpose of the clitoris, but from the point of view of why evolve something that doesn't make you want to have a baby, this is one possibility)
2)bonobo females do hump each other face-to-face. Perhaps the clitoris also evolved to encourage social-sexual behavior among females.
I can think of two ways that female orgasm would increase the likelihood of fertilization, and thus select for whatever trait was causing/allowing for female orgasm.
1) Encouraging females to engage in PIV sex in the first place.
2) Pulling ejaculate toward the cervix, upping the chances of fertilization.
I don't think the inability to orgasm stops many women from engaging in PIV sex. Even without orgasm, sex can be greatly pleasurable.
As for #2, I don't think there's ever been a study that tested the fertilization rate with and without female orgasm. It'd be interesting, but full of confounding factors.