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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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1 posted on 12/09/2005 7:01:05 AM PST by billorites
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To: billorites

Where is the mandatory pic of the squirrel testes?


2 posted on 12/09/2005 7:02:40 AM PST by dinoparty (In the beginning was the Word)
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To: billorites

1...2...3 testes, testes, testes. Is this thing on?


3 posted on 12/09/2005 7:02:52 AM PST by cripplecreek (Never a minigun handy when you need one.)
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To: billorites

This probably explains why Janet Reno is dumber than a bag of rocks.


4 posted on 12/09/2005 7:03:17 AM PST by Alberta's Child (What it all boils down to is that no one's really got it figured out just yet.)
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To: billorites

Oh, this should be good. Our Friday fun thread???


5 posted on 12/09/2005 7:04:43 AM PST by mlc9852
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To: Alberta's Child
This probably explains why Janet Reno is dumber than a bag of rocks.

Quit it! Coffee hurts when it comes out your nose.....

6 posted on 12/09/2005 7:05:32 AM PST by Thermalseeker
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To: dinoparty
Where is the mandatory pic of the squirrel testes?

PS: Sorry in advance if I offended anyone!

7 posted on 12/09/2005 7:05:43 AM PST by CarrotAndStick (The articles posted by me needn't necessarily reflect my opinion.)
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To: billorites
I notice that although they equate brain size with intelligence, they do not note that men tend to have larger brains than women.
8 posted on 12/09/2005 7:05:58 AM PST by marktwain
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To: CarrotAndStick

9 posted on 12/09/2005 7:07:13 AM PST by Mr. Brightside
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To: billorites

Insert AC/DC music please:

http://www.lyricsdomain.com/1/acdc/big_balls.html


10 posted on 12/09/2005 7:08:57 AM PST by ConservativeStatement
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To: marktwain
But if the girls are putting it about, it is better to be virile and dim, than impotent and smart.

Yeah, right. Where is the smaller-"brained" Neanderthal Man now?


11 posted on 12/09/2005 7:09:07 AM PST by CarrotAndStick (The articles posted by me needn't necessarily reflect my opinion.)
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To: marktwain
although they equate brain size with intelligence, they do not note that men tend to have larger brains than women.


12 posted on 12/09/2005 7:09:35 AM PST by Mr. Brightside
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To: Thermalseeker
LOL.

I wish I could take full credit for that, but I must give proper credit to someone else . . . a caller to a New York talk radio show in late December about ten years ago who called in on a "What are your Wishes for the New Year?" segment and told the host that wanted to wish Janet Reno well in the coming year as she faced a tough battle against prostate cancer.

13 posted on 12/09/2005 7:10:44 AM PST by Alberta's Child (What it all boils down to is that no one's really got it figured out just yet.)
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To: billorites
One, who came up with this theory and under what level of inebriated condition?

Two, who could possibly write the request for government funding for this study with a straight face?

14 posted on 12/09/2005 7:11:55 AM PST by robertpaulsen
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To: billorites

Dammit! Was not IBTS (in before the squirrel)


15 posted on 12/09/2005 7:11:59 AM PST by add925
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To: CarrotAndStick
LMAO.....knew it had to show up. I just read the headline and knew it would be here...
..???...and darn it I don't know how I got through reading all those hard words.

*snicker*

Doogle
16 posted on 12/09/2005 7:13:34 AM PST by Doogle (USAF...7thAF ..4077th TFW...408th MMS..Ubon Thailand.."69",,Night Line Delivery..AMMO)
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To: CarrotAndStick

I married him! LOL


17 posted on 12/09/2005 7:14:23 AM PST by mlc9852
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To: billorites

18 posted on 12/09/2005 7:15:14 AM PST by Dallas59 (“You love life, while we love death"( Al-Qaeda & Democratic Party)
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To: billorites

Finally, a thread that's perfect for posting this:

http://www.davesdaily.com/videoclips/17-pianoballs.htm


19 posted on 12/09/2005 7:15:48 AM PST by savedbygrace (SECURE THE BORDERS FIRST (I'M YELLING ON PURPOSE))
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To: billorites

Maybe this will put a stop to G. Gordon Liddy's bragging about his "grapefruit sized" nuts.


20 posted on 12/09/2005 7:17:55 AM PST by Recovering Hermit
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