After reading a thread about male lactation, something I am still not sure can happen w/o drugs, but assuming all it takes is attaching a baby to a male nipple and it will activate and supply all needed milk for the little one, why is there a female boobie?
If male lactation is possiable, then the entire boobie does not seem needed. Perhaps positioning the baby might be a bit easier with a boobie, but that hardly seems worth the trouble of carrying those jugs around. The only thing I can come up with is a biological signal to males that basically say that “Hey, I can have your baby”, this would avoid confusion with female children.
Males have nipples etc because females have them and require them - theyre part of the construction process that is common to both males and females - there are sex-specific modifications along the way, but they start out the same in both males and females.
Lactating glands do take up varying amounts of space AFAIK. In the one picture from the male lactation story linked to from the other thread, the guy did not appear to have ‘man boobies’ or the like, but he was fairly buffed and it might be hard to tell if there was lactation tissue underneath those pecs or something. The male lactation hormones might not activate too much in men… i would imagine that women that are fairly flat chested can also breast feed without too much trouble. That doesn’t mean there isn’t an evolutionary advantage in having more in some cases. (Was it possible that stone age chicks had more children to feed at a time? )
Breasts also have a lot of fat tissue IIRC… possibly so that even in times of famine and food shortage the babies would be more likely to survive.
Why do mature human females have visibly pendulous breasts even when not lactating, when other primates do not?
The answer: Your guess is as good as mine.
Maybe it’s the same reason why women have concealed ovulation (again, unlike other primates). Many researchers believe it is a deceptive display meant to trick males into doing good things for them. To wit:
Again, though, why would humans develop this “strategy” but not, say, chimps? Why don’t she-chimps have big breasts to lure in the he-chimps?
Who knows. Perhaps it is related to our social structure, which generally requires a much greater concentration of individuals, a greater interaction between males and females (than, say, chimps, where males and females are generally more segregated), and a greater degree of cooperation among group members (most human groups can’t survive the degree of violent competition you see among chimps … our competition is much more subtle).
Oh, and specifically, maybe these various methods of obfuscating when females are ovulating (and thus available for mating) or lactating (and thus unavailable for mating, but in need of extra food) helped to increase group cohesion, allowing a group that possessed them to outcompete groups that did not.
Oh. Re-reading Kanic’s OP, I see that I made a great deal more of this topic than seems appropriate.
Kanic: Because you really DO need all that room to store all that breast tissue and milk. Yes, males can sometimes lactate, but rarely can they lactate enough sheer volume of milk to keep an infant alive (often, many females can’t do that).
Furthermore, from a cold evolutionary standpoint, it is probably not to the male’s benefit to nurse a child if the mother dies. After all, he can rarely be 100% sure that the child is his. The mother can be sure it’s hers (it came out of her body, after all, and in many cultures never left her side afterward), but the mother’s mate (the father) can never tell for certain that he was the only potential sperm-donor. Why risk your own potential starvation to raise someone else’s genes when you could instead try to knock up another woman?
Consider that even women with A cups or smaller can and routinely do nurse. Now consider that there are women with mammaries many times larger. Obviously, most of that tissue is serving a purpose other than lactation. I’d say that your conclusion of sexual signals is perfectly reasonable. Just like long hair on women or beards on men, it’s an indicator that a female is female (and in the case of breasts, that she’s sexually mature).
Desmond Morris, in The Naked Ape, speculated that enlarged breasts evolved in female humans when the mating style switched from mounting from the rear to front-to-front intercourse as humans became more bipedal. Large female buttocks were already a strong sexual stimulus for a male while mating from the rear. Large breasts developed in mimicry of buttocks to provide a similar stimulus when mating took place from the front.
“Large” breasts developed when females began to walk upright. This is also when pubic hair began to be displayed. Both are displays of reproductive fitness.
As males began leaving camp on hunting trips, non-estrous sex meant it was more likely that a father would share the kill with his family, and not some female that just happened to be in estrous.
I heard a hypothesis to the effect that breasts were advantageous in nursing an infant with a flat face (like modern humans have) and that a flat face was part of the package that the larger brain comes in.
It has also been speculated that large or pendulous breasts allow a woman to nurse while she is carrying an infant around on her hip.
The sexual selection argument, though, seems the most plausible. Generally, when you are is trying to figure what might be the purpose of some seemingly useless, even inconvenient, feature of an animal, nine times out of ten the answer has something to do with sexual selection.
While lactating breasts do store a certain amount of milk, they do not store up an entire feed’s worth. What is stored, furthermore, is very low in fat (this is called foremilk) and a baby who drinks nothing else will grow poorly and experience gastric difficulties.
Most milk is produced on demand, while the baby is suckling (this feels, if you can understand what I mean, the way water sounds when trickling through pipes). Large amounts of mammary tissue are not required for storage.
I have a video here which my kids love dearly, about baby animals in zoos. There’s a segment about a mother gorilla with her newborn baby, and the mother gorilla has very human-looking, pendulous breasts. It’s interesting, and I use the video to explain to the girls that humans have “nursies” or breasts all the time, and they will have them when they grow up, but gorillas only have them when they’re feeding a baby. This led one of my 5 year olds to say “But I’m not going to have any children when I grow up. Why do I have to have nursies?” Well, kid, that’s biology for you.
If it is a biological indicator of sexual maturity It would follow that other primates would only need this indicator if they take about the same amount of years to reach sexual maturity. If they matured faster this indicator does not seem as important.
This one comes up with great frequency. Not surprising considering the content and the number of young males on the Board. But you guys gotta learn t use he Search feature.
Again, I endorse the Desmnd Morris theory of Buttock Mimickry. This one rally does seem to originate with Morris (he’s annoyingly chary in giving cites himself), and there’s more to it than just buttock mimickry alone – asee his books. But the gist of it is that , as stated above, re-positioning of the sexual signals occurred when e gained an upright stance. It also probably has to do with humns being always sexually ready, rather than having breeding seasons (which is why the structure is permanent – female chimp buttocks swell and redden only when they’re sexually ready). Hmans have pronounced butticks nique in the primate world because o our upright stance (they provide the muscle power to keep s upright)
As for those who object that anthropologits don’t endorse this, you’re just not reading the right ones. See Martin Harris’ Our Kind, for instance.
Finally, humans aren’t he only primates with female chest echoes of buttock markings – see the Gelada Baboon for another example. And Mandrills and other primates have male genital/face marking echoes.
The male lactation hormones might not activate too much in men… i would imagine that women that are fairly flat chested can also breast feed without too much trouble. That doesn’t mean there isn’t an evolutionary advantage in having more in some cases. (Was it possible that stone age chicks had more children to feed at a time? 