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December 31
Neuroscience Ph.D. ************************** Passionate about science education and outreach; enjoys a great discussion about the intersection of science and everyday life *************************** Currently a biomedical researcher at a Harvard University hospital - Areas of expertise: endocrinology, appetite and metabolism, neuroscience, biochemistry, molecular biology *************************** Areas of interest: science and art, science and society, science policy, books/films/music, reading great magazines, travel, learning new things and sparking new ideas, gardening/nature *** All Content Copyright Aliquot - do not reproduce without express permission ***

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DECEMBER 5, 2009 2:51PM

fellatio - humans do it, bonobos do it, even lil' bats do it

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fruit bat aaas

fruit bat photo from AAAS


Only human??  If you're like me, you're constantly adding to your mental list of traits that were once attributed only to humans, but now we know they're  not unique to homo sapiens.  Now, you can add fellatio to that list.


 The fruit bat is one species recently added to the short list of animals we now know practice fellatio.  According to ScienceNow, the authors speculate that the fellatio may be beneficial for several reasons:

"One idea is that it may facilitate sperm transport. Or it could keep males occupied--and thus away from rival females. Fellatio may also offer protection against sexually transmitted diseases, based on the antimicrobial properties of saliva.....Although it's possible ...that bats are just being sexually playful, like their human and bonobo counterparts."

Here is the abstract of this recent paper from the open-access PLOS journal by Tan et al.  (see link below for free full text):


Oral sex is widely used in human foreplay, but rarely documented in other animals. Fellatio has been recorded in bonobos Pan paniscus, but even then functions largely as play behaviour among juvenile males. The short-nosed fruit bat Cynopterus sphinx exhibits resource defence polygyny and one sexually active male often roosts with groups of females in tents made from leaves. Female bats often lick their mate's penis during dorsoventral copulation. The female lowers her head to lick the shaft or the base of the male's penis but does not lick the glans penis which has already penetrated the vagina. Males never withdrew their penis when it was licked by the mating partner. A positive relationship exists between the length of time that the female licked the male's penis during copulation and the duration of copulation. Furthermore, mating pairs spent significantly more time in copulation if the female licked her mate's penis than if fellatio was absent. Males also show postcopulatory genital grooming after intromission. At present, we do not know why genital licking occurs, and we present four non-mutually exclusive hypotheses that may explain the function of fellatio in C. sphinx.



Free full text of article in PLOS online:

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You godless squints will all burn in hell forever!
Oh Andy.... I must have offended your delicate sensibilities.

Tom, glad the animal kingdom makes it sound like fun!
Now, that's the most fascinating thing I've heard all day.
I want to know whether what's good for the gentleman bat is good for the lady bat, too. In other words, does he reciprocate?
Thanks, susanmihalic.
Eva T. Made Vaudeville, here is an answer directly quoted from the authors of the study:

"The behaviour presumably favours the
donor, although it may also benefit both partners especially if
fertilization success is increased. It is conceivable that the female
manipulates the male by increasing sexual stimulation, so that she
ultimately benefits."

Apparantly, the male bat does not reciprocate (or at least, this study did not observe that). Cunnelingus (sp?) may have been observed in non-humans by other research groups, but I'd have to look into it first!
Aliquot, if you find out the answer, will you write another post to let us know? Inquiring minds and all that. . . .
Add that to my list of odd questions,lol

I always wondered what an erect penis weighed? Anybody know?
As an update, I have done a search for cunnilingus (correct spelling here) in the scientific literature and come up with only 52 articles (fellatio, by contrast, returns 116 articles to date - yes, science is still very male-centric). None of the cunnilingus articles are in non-humans, however this does not mean that the act has not been observed in the animal kingdom. (I personally think that our anthropocentric tendencies would lead us to believe that we possess unique sexual behaviors, but in fact animals partake in very similar hetero- and homosexual acts as us.)

As for your question LadyMiko, have not found a reliable answer yet - but this area of biology is certainly not my specialty. Will update you if I find any data on this!

Thanks for all your comments!