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1/25/2018 7:38:29 AM
Posted: 1/24/2006 8:25:28 PM EST

When it comes to bats, size matters

Tuesday, January 24, 2006; Posted: 10:17 a.m. EST (15:17 GMT)

"It turns out size does matter," said Syracuse University biologist Scott Pitnick.

SYRACUSE, New York (AP) -- For some male bats, sexual prowess comes with a price -- smaller brains.

A research team led by Syracuse University biologist Scott Pitnick found that in bat species where the females are promiscuous, the males boasting the largest testicles also had the smallest brains. Conversely, where the females were faithful, the males had smaller testes and larger brains.

"It turns out size does matter," said Pitnick, whose findings were published in December in "Proceedings of the Royal Society: Biological Science," an online journal.

The study offers evidence that males -- at least in some species -- make an evolutionary trade-off between intelligence and sexual prowess, said David Hoskens, a biologist at the Center for Ecology and Conservation at the University of Exeter in England and a leading authority on bats' mating behavior.

"Bats invest an enormous amount in testis, and the investment has to come from somewhere. There are no free lunches," said Hoskens, who did not participate in the study.

The relationship between the breeding system and relative brain size has received little investigation, said Pitnick, who teaches evolution and population biology and researches topics such as sexual selection and sexual conflict.

Bats are the second largest group of mammals (behind rodents) with about 1,000 known species. Because of their exceptional navigational and flying abilities, bats have been the subject of countless studies, providing Pitnick and his colleagues -- Kate Jones of Columbia University and Gerald Wilkinson of the University of Maryland -- with a bounty of data without having to slink off into caves.

Pitnick's team looked at 334 species of bats and found a convincing contrast in testes size. In species with monogamous females, males had testes starting at 0.11 percent of their body weight and ranging up to 1.4 percent.

But in species where the females had a large number of mates, Pitnick found testes ranged from 0.6 percent to 8.5 percent of the males' mass (in the Rafinesque's big-eared bat).

"If female bats mate with more than one male, a sperm competition begins," Pitnick said. "The male who ejaculates the greatest number of sperm wins the game, and hence many bats have evolved outrageously big testes."

Promiscuity is known to make a difference in testicle size in some other mammals. For example, chimpanzees are promiscuous and have testicles that are many times larger than those of gorillas, in which a single dominant male has exclusive access to a harem of females.

Large brains, meanwhile, are metabolically costly to develop and maintain.

Pitnick's research suggested that in those bat species with promiscuous females, the male's body used more of its energy to enhance the testes -- giving it the greater adaptive advantage -- and lacked the energy it needed to further develop the brain.

The study found that in more monogamous species, the average male brain size was about 2.6 percent of body weight, while in promiscuous species, the average size dipped to 1.9 percent.

Link Posted: 1/24/2006 8:35:29 PM EST
Mine do already.
Link Posted: 1/24/2006 8:36:23 PM EST

Originally Posted By ProfessorEvil:
Mine do already.

I hear ya, -- little brother.
Link Posted: 1/24/2006 8:40:57 PM EST
both, or each?
Link Posted: 1/24/2006 9:19:49 PM EST

(In Before The 'Legalize It' Poll)

Link Posted: 1/25/2006 1:32:58 AM EST
where is the pic of bat cock?

I would put bat cock in this thread, but I think it would violate the CoC
Link Posted: 1/25/2006 1:38:22 AM EST
Link Posted: 1/25/2006 1:40:27 AM EST
This needs more batcock.
Link Posted: 1/25/2006 6:09:44 AM EST

With all the cheating that seems to go on within *this* population (arfcommers), I would not be surprised to see your presumption proven empirically.

It would also be interesting to see how humans (as a whole) compare with bats and other species which have been studied. Also, from an intercultural studies perspective, it would be interesting to note the level of variance (if any) between genetically-distinct human groups.
Link Posted: 1/25/2006 6:14:18 AM EST
You know, when someone is standing foot deep in guano in some awful amonia filled cave and is trying to capture a bat so they can play with its balls, you would think that they would figure out how stupid their job is and go do something productive.

By the way, does anyone else feel "unclean" after hearing "testicles" and "free lunch" in the same sentence??
Link Posted: 1/25/2006 6:33:22 AM EST
shameless bump because my post is extremely funny.
Link Posted: 1/25/2006 6:55:20 AM EST

Originally Posted By John_Wayne777:
shameless bump because my post is extremely funny.

Shameless bump because your post wasn't that funny.


Link Posted: 1/25/2006 6:55:32 AM EST

Originally Posted By cmjohnson:
I don't see how it would be a COC violation. I'm tempted to put it up myself.


IIRC the last time it was posted the thread was locked and so was the poster. I could be wrong though
Link Posted: 1/25/2006 7:01:21 AM EST
Link Posted: 1/25/2006 7:04:46 AM EST
I wonder how much Federal tax money was spent to find out that completely worthwhile bit of information.........

Link Posted: 1/25/2006 7:46:47 AM EST
"Claire, you wanna see a picture of a guy bat with elephantitis of the nuts?"
Link Posted: 1/25/2006 7:52:09 AM EST
This thread is tEh baT gHeY !!

Link Posted: 1/25/2006 7:54:42 AM EST

Originally Posted By bastiat:
both, or each?

Link Posted: 1/25/2006 2:54:42 PM EST
It's a proved fact that humain guys wif big penile units ain't too smart,
Link Posted: 1/25/2006 4:31:04 PM EST

Originally Posted By 10mmFan:
It's a proved fact that humain guys wif big penile units ain't too smart,

Too bad you have the worst of both worlds.
Link Posted: 1/25/2006 5:23:50 PM EST
Scrotum Elephantitis
Link Posted: 1/25/2006 5:57:38 PM EST

Link Posted: 1/26/2006 5:07:38 AM EST
Well MrClean your well thought out and beautifully constructed sentence speaks volumes 0f your "little" problem!
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