The Scrotum Is Nuts

This is a repost promoting content originally published elsewhere. See more things Dan's reposted.

Why are testicles kept in a vulnerable dangling sac? It’s not why you think.

Some of you may be thinking that there is a simple answer: temperature. This arrangement evolved to keep them cool. I thought so, too, and assumed that a quick glimpse at the scientific literature would reveal the biological reasons and I’d move on. But what I found was that the small band of scientists who have dedicated their professional time to pondering the scrotum’s existence are starkly divided over this so-called cooling hypothesis.

When I first saw this article and its clickbait subtitle, I almost didn’t read it. After all, I thought I knew the answer: that testicles hang outside the body (and in a sac with a large surface area) because this helps them to keep cool, which aids the production of sperm. It turns out that this is far from an established fact, and a significant number of biologists dispute it and/or subscribe to one of a number of alternate hypotheses. Read for yourself…