Different in degree or kind: only humans have big breasts (Introduction)

by David Turell , Saturday, March 09, 2019, 01:28 (2087 days ago) @ David Turell

Another nutty difference in kind. We are the only mammals that develop larger breasts long before having a pregnancy to stimulate breast enlargement for lactation as in all other mammals. Human breasts also maintain their larger volume after breasts feeding is over. In all others they shrink back to roughly former size.

http://blogs.discovermagazine.com/crux/2019/03/06/why-do-humans-have-breasts/#.XIMPgHdFyze

"In other primate species, only pregnant or lactating females have bosoms. The animals stay flat-chested for the rest of their lives. In humans, pubescent girls accumulate fat around their milk glands, which stays for life and seems to hold sex appeal in every culture. Those permanent, alluring mounds of fat on women’s chests are indeed an evolutionary anomaly, begging for an explanation.

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"Whether or not breasts first served as energy banks or handle bars for mothers and infants, they eventually caught the attention of males. This is why most researchers assume sexual selection has been at work: They argue that over the course of human evolution, permanent breasts helped females attract mates. Like the ostentatious feathers of male peacocks, breasts served as a message to the opposite sex, “Hey, look at these! Reproduce with me!”

"And in the case of peacock feathers, and potentially breasts, there’s truth in advertising. The more spectacular the feathers, the healthier the bird, and therefore this trait is what evolutionary biologists call an honest signal: a reliable indicator of an animal’s quality as a mate or parent. It’s a feature potential suitors can assess before deciding, “Oh yeah, I want to make babies with this individual.” As for breasts, some hypotheses in the sexual selection camp contend the fat mounds are an honest signal of a woman’s mate-worthiness.

:In Western populations, some studies have shown that most men prefer women with narrow waists and large breasts

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"The researchers measured two female sex hormones — progesterone and a form of estrogen (E2) — from spit samples, collected from 119 healthy Polish women every morning for the duration of one menstrual cycle, or roughly one month. Not considering waists, breast size alone related only to E2 levels. Because estrogen plays a crucial role in girls developing their womanly figures, this may suggest that breasts are just a side effect of gaining healthy voluptuous fat overall.

"But the study also found that women with large breasts and narrow waists had higher values for both hormones — and the combo of these hormones predicts pregnancy success. This led the researchers to conclude that at least among these Polish women, “the cultural icon of Barbie as a symbol of female beauty seems to have some biological grounding.”

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"As for men’s taste in breasts, numerous studies have tried to uncover universal preferences, which may be biologically programmed.

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"Men’s preferences seem influenced by number of factors, including: culture (says one study, “Brazilians preferred larger breasts and buttocks than Czechs”), socio-economic status (larger breasts for lower status men), sexual habits, (larger for men in short-term, non-committal relationships), body image, (larger for men who rated themselves more attractive), sexist attitudes (larger for men hostile toward women) and even hunger (hungry British men liked bigger breasts than fed participants). And some experiments focused on other qualities than size, such as how perky or symmetrical breasts are.

"Suffice to say, if there are underlying, biologically evolved preferences for certain breast qualities, cultural and individual factors can override them. More research is certainly needed. "

Comment: Biologically speaking, human breasts are modified sweat glands surrounded by fat. Flat or full they all give enough milk when required. In this country padded bras and breast enhancement surgery attest to the visual importance of size, both for men, but also for women who want to improve their personal self image. As a physician I have been asked by female patients for a good plastic surgeon, and in one instance a patient was so grateful for the result, she made an appointment just to undress and show me! Black men here are well known to watch for big buttocks on first look. Therefore, we need a great just-so story to answer the issue of 'why' in each sub-culture..