What's With Testicles?

[RidiculousName]

Like most mammals human males are bigger than human females. We also tend to be the ones that engage in fighting. Obviously, this is largely because women are the ones who can get pregnant. However, it puzzles me that we're one of the few mammals where the males have testicles on the outside. Why? What purpose does it serve? Women have way more and bigger reproductive organs than we do. Why is that essential part of our baby-making system left vulnerable, protruding away from the rest of the body?

 

[Todd Feinman]

Like most mammals human males are bigger than human females. We also tend to be the ones that engage in fighting. Obviously, this is largely because women are the ones who can get pregnant. However, it puzzles me that we're one of the few mammals where the males have testicles on the outside. Why? What purpose does it serve? Women have way more and bigger reproductive organs than we do. Why is that essential part of our baby-making system left vulnerable, protruding away from the rest of the body?

More viable sperm are created in a cooler environment.

 

[Dan Howard]

Testes work in conjunction with the scrotum. The scrotum expands and contracts to maintain a constant temperature. When cold it contracts to draw them closer to the body.

 

[AlpinLuke]

More viable sperm are created in a cooler environment.

Correct. But this doesn't explain the difference from other mammal species. Our species has adopted a quite efficient survival strategy: the male individuals keep on producing sperm [we don't do it only in some periods of the year, like cats, just to say, we do it every day] to ensure a high probability to have children. This requires that the sperm is always fertile. So the "production" has to be optimal. An other problem of humans is that the man cannot be totally certain that the woman is fecund [again, a woman is not like a female cat which shows in an evident and instinctive way to be "ready" to get pregnant], the man has to keep on trying ...

So to keep that part of the body at the best and most suitable temperature is a necessity.

Now ... did it came the chicken before the egg or the other way round? It's not impossible that during evolution, to have external testes has caused the development of our sexual habits.

 

[Todd Feinman]

Women's menstrual cycles will synchronize, based on pheromones. Women also emit pheromones when they are fertile, that can be an indicator to men. Women also exhibit sex flush in face and lips; this is masked by lipstick. Male masturbation is not to be underestimated; there have even been studies that suggest it wards off particular types of cancer.

 

[Linschoten]

You don't need to ask this about human beings specifically, it's an ape and monkey thing.

 

[aggienation]

The Evolutionary Origin of Descending Testicles

 

[aggienation]

Women's menstrual cycles will synchronize, based on pheromones. Women also emit pheromones when they are fertile, that can be an indicator to men. Women also exhibit sex flush in face and lips; this is masked by lipstick. Male masturbation is not to be underestimated; there have even been studies that suggest it wards off particular types of cancer.

Lipstick isn't to hide anything, for lighter skinned humans its to accentuate the lips, an erogenous zone, and to appear healthy as brighter equals better blood flow. And to mimic the arousal of the female genitals after they become engorged with blood, the upper lips look like the bottom ones.

 

[Todd Feinman]

Does a Splash of Red Make a Woman More Attractive?

 

[aggienation]

There is a scene in the movie Schindler's List where female Jews in a concentration camp are about to stand for a medical selection, based on true accounts. They were slapping themselves in their cheeks, pricking fingers to smear blood on their lips and cheeks. To appear healthy. Pale isn't healthy, red is (at least for light skinned people).