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Bats and balls: Bigger testes mean smaller brains
Economist.com ^ | December 8, 2005

Posted on 12/09/2005 7:01:03 AM PST by billorites

MEN are often accused by women of, to put it bluntly, having their brains in their balls. A joke, of course. But perhaps not as much of one as people might like to think. For a study of bats carried out by Scott Pitnick, of Syracuse University in New York State, and his colleagues, suggests that there really is a trade-off between the two organs.

With about 1,000 species, bats are the second-largest group of mammals (rodents are top), so there is plenty of material for interspecies studies. Dr Pitnick's project, published in this week's Proceedings of the Royal Society, looked at brain size and testis size in 334 of those species. Sadly, the team's research budget did not allow it to jet around the world and gather data directly. Instead of visiting bat caves, the scientists visited their universities' libraries. But bats are a well-studied group, and so the team was able to gather pertinent data on the anatomy and behaviour of a third of them.

The hypothesis they were testing came in two parts. The first was that in any given species, the average male's testis size as a fraction of body weight will depend on the behaviour of that species' females—in particular, how promiscuous those females are. The second was that, given that brain tissue and testis tissue are among the most expensive to maintain physiologically, and that bats have a very tight energy budget, bigger balls would result in smaller brains.

The team knew, from work done some time ago, that the first part of their hypothesis is true in primates. Greater promiscuity in females does, indeed, lead to bigger testes, presumably because a male needs to make more sperm to have a fighting chance of fathering offspring, if those sperm are competing with sperm from a lot of other males. Gorillas, which discourage dalliances between other males and the females of their harem, have small testes. Chimpanzees, among whom females mate widely, have large ones. Human testes lie between these two extremes.

And so it proved in bats. Bat testes range from 0.11% of body weight in the African yellow-winged bat, to a whacking 8.4% in the generously endowed Rafinesque's big-eared [sic] bat. (The largest primate testes by contrast, those of the crab-eating macaque, are a mere 0.75% of body mass.) And the small balls were indeed found in species where females were monogamous (though they might be members of harems), while the large ones were found in species where females mated widely.

Brain size, by contrast, and just as predicted, varied in the opposite direction. Nor was it dependent on the level of male promiscuity. In the bat world, it seems that you do not have to be cleverer to be a libertine than to be a faithful husband. But if the girls are putting it about, it is better to be virile and dim, than impotent and smart.


TOPICS: News/Current Events
KEYWORDS: balls; brain; neener; sperm; testes; testicles; vinny
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To: savedbygrace

I've seen that video before on TV. Man, he is amazing! Even the music is enchanting!


21 posted on 12/09/2005 7:18:06 AM PST by CarrotAndStick (The articles posted by me needn't necessarily reflect my opinion.)
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To: billorites
Greater promiscuity in females does, indeed, lead to bigger testes,

It is crap like this that I have very little faith in studies. Their may be a relationship between promiscuity and testes but to claim a reason is pure speculation. For example, the opposite might be true. Female promiscuity might be the result of larger testes.

22 posted on 12/09/2005 7:19:14 AM PST by Raycpa
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To: billorites
How'd you like to be a lab assistant on that study?
23 posted on 12/09/2005 7:21:06 AM PST by RichInOC ("...okay, turn your head and cough." *squeak!*)
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To: billorites

They call me "Raisinettes."


24 posted on 12/09/2005 7:21:48 AM PST by manic4organic (We won. Get over it.)
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To: billorites

What a waste of money. They could have come to the same conclusion by looking at the new TV season.


25 posted on 12/09/2005 7:25:28 AM PST by ArmstedFragg
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To: billorites
Brain and testicular size do not correlate with function, though further generalization becomes invalid.

As for the alleged inverse proportionality of brain and testicular function--I hate to brag but--I am the example that disproves both the aphorism and the results of this experiment (not to mention the invalidity of generalizations).

26 posted on 12/09/2005 7:40:13 AM PST by Savage Beast ("Oprah: The light that shines so gently on those who need it most." ~Sidney Poitier)
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To: CarrotAndStick

27 posted on 12/09/2005 7:48:29 AM PST by Graymatter
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To: Savage Beast

N-V-T-S, Nuts!


28 posted on 12/09/2005 8:06:53 AM PST by LearsKent
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To: billorites

no wonder I couldn't pass the Bar Exam the first time.


29 posted on 12/09/2005 8:08:39 AM PST by jw777
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To: MassRepublicanFlyersFan

You silly duck, that song referred to big parties and had nothing to do with testes!


30 posted on 12/09/2005 8:34:50 AM PST by dinoparty (In the beginning was the Word)
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To: billorites

The colder it gets, the smarter I get.....


31 posted on 12/09/2005 8:35:24 AM PST by RightResponse (What if the Left, just got up and .....)
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To: Savage Beast

You mean you are dumb AND have small nads? j/k


32 posted on 12/09/2005 8:41:30 AM PST by dinoparty (In the beginning was the Word)
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To: RichInOC

LOL, what resume material!
"2004-2005 Played an integral role in the study of the correlation between ball size and smarts."


33 posted on 12/09/2005 8:43:33 AM PST by dinoparty (In the beginning was the Word)
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To: dinoparty

Ran this awhile back.

A study conducted by UCLA's Department of Psychiatry has revealed that the kind of face a woman finds attractive on a man can differ depending on where she is in her menstrual cycle.

For example: If she is ovulating, she is attracted to men with rugged and masculine features.

However, if she is menstruating, or menopausal, she tends to be more attracted to a man with scissors lodged in his temple and a bat jammed up his ass, while he is on fire.


34 posted on 12/09/2005 8:54:26 AM PST by edcoil (Reality doesn't say much - doesn't need too)
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To: edcoil

Would that be "bat" as in the animal or as in baseball bat? Its very important, because the scissors have already been inserted and the kerosene is ready.


35 posted on 12/09/2005 9:01:22 AM PST by dinoparty (In the beginning was the Word)
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To: manic4organic

I think South Park spoofed Hooters with a place called Raisins. :-)


36 posted on 12/09/2005 9:38:09 AM PST by ConservativeStatement
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To: billorites

Explains the Republicans in Congress I guess.


37 posted on 12/09/2005 9:39:54 AM PST by <1/1,000,000th%
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To: dinoparty

Yep. You got my number.


38 posted on 12/09/2005 4:52:29 PM PST by Savage Beast ("Oprah: The light that shines so gently on those who need it most." ~Sidney Poitier)
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To: billorites

But if this were true, wouldn't the average Republican Senator have a head the size of '72 El Dorado?


39 posted on 12/09/2005 4:54:46 PM PST by Redcloak (We'll raise up our glasses against evil forces singin' "whiskey for my men and beer for my horses!")
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To: Alberta's Child
This probably explains why Janet Reno is dumber than a bag of rocks.

"bag of rocks..." Heh, heh! Yeah! He said bag!

Well, her head does look like one big teste, wouldn't ya say! An interesting development to the entire notion.

40 posted on 12/09/2005 4:55:00 PM PST by Fruitbat
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