Quote:
Originally Posted by davidmash
Then tuck the little guys away in the pelvis. Nature came up with the platypus, I think it can come up with a way to protect my nuts and not affect performance or utility.
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That's what I had in mind. The female organs are all well protected without some dinosaur like plate, or at least more so than my poor li'l cajones. It's hard to imagine why having them hanging out in the open would have been selected for. But here we are so there must have been some reason.
OK, here we go:
http://www.scientificamerican.com/blog/post.cfm?id=why-do-human-testicles-hang-like-th-2009-11-19
In many respects, the activation hypothesis serves to elaborate what many of us already know about descended scrotal testicles: that they serve as a sort of “ cold storage” and production unit for sperm, which keep best at lower body temperatures. But it goes much further than this fact, too. It turns out that human testicles display some rather elaborate yet subtle temperature-regulating features that have gone largely unnoticed by doctors, researchers and laymen alike. The main tenet of the activation hypothesis is that the heat of a woman's vagina radically jumpstarts sperm that have been hibernating in the cool, airy scrotal sack. Yet it explains many other things too, including why one testicle is usually slightly lower than the other, why the skin of the scrotum becomes more taut and the testicles retract during sexual arousal, and even why testicular injuries--compared to other types of bodily assault--are so excruciatingly painful to men.
www.epjournal.net/filestore/ep07517526.pdf
(whoops, that link doesn't work - I can go to it by clicking on the search result, which yields a pdf file with no URL - the above URL is in the result box - 3rd one down here, title line is:
[PDF] On the Origin of Descended Scrotal Testicles: The Activation ...)
http://search.yahoo.com/search;_ylt=A0oG7lQwP5JNolIAWS1XNyoA;_ylc=X1MDUCMyMTQyMzU3MDg5BF9yAzIEYW8DMQRmcgN5ZnAtdC03MDEEZnIyA3 NidG4EaG9zdHB2aWQDWDJWRy5Fb0c3djVvNnNJY1M2bXFNUUYuMERZT0EwMlNQekFBRFowdwRuX2dwcwMwBG9yaWdpbgNzcnAEcX VlcnkDZXZvbHV0aW9uIG9mIHRlc3RpY2xlIHNhY2sEc2FvAzIEdnRlc3RpZANERkQ1?p=evolution+of+testicle+sack&fr2=sb-top&fr=yfp-t-701&type_param=
Introduction
It is almost unthinkable to ask why ovaries do not descend during embryological development and emerge outside the female’s body cavity in a thin, unprotected sack. Evolution is based on reproductive competition among individuals for genetic representation in future generations. The integrity of the gonads is of paramount importance when it comes to reproduction. Because of vulnerability to damage, insult, and temperature variation, unprotected ovaries located outside the body cavity would be an enormous handicap/serious reproductive disadvantage. The same reasoning applies with equal force to the testicles. But unlike ovaries, descended testicles located outside the body cavity in the scrotum are common among many mammals in spite of all the obvious risks and disadvantages.
We propose a simple mechanism in the common ancestry of mammals (or at least placentals) that may have evolved to promote descended, scrotal testicles. We also examine a number of adaptations that appear to have evolved to maintain scrotal testicles and minimize the costs of this peculiar gonadal arrangement. Finally we offer testable predictions about the minority of mammals without descended testicles (testicondy).