NSFW Science: Fruit Bat Fellatio

Yeah, I'm just going to put this whole NSFW thing behind the jump. Read on for an in-depth look at bat blow-jobs, and insights into the evolution of such work, in general.

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Figure 3. Copulation duration in Cynopterus sphinx according to whether the female licks the male's penis (Licking) or not (No licking). Means and standard errors are shown. Vignette shows a female performing fellatio, drawn by Mei Wang. (I assure you, I am not making any of this up.)

So, why do you think blow jobs happen?

This is not a trick question.

Most of us would probably go for the, "Hey, that feels nice," theory of oral sex. But researchers Min Tan, Gareth Jones, Guangjian Zhu, et. al., think there may be more to it than simple pleasure. As part of their attempt to prove a practical function for oral sex, the team conducted a study of the fellatio habits of fruit bats. The paper was published October 28 in the journal PLoS ONE. You can read the whole thing online.

The basic idea here is that there might be some benefit to blow jobs (beyond the obvious) and the fact that bats who engage in fellatio have longer sessions of sex than bats who don't could be evidence in favor of that theory. Why? Because it's showing that oral sex is correlated with a change in behavior and, the scientists theorize, there may be reasons why that behavioral change is beneficial to the animals. How beneficial? The team theorizes that oral sex could be doing everything from increasing the chances of sperm fertilizing egg, to killing bacteria on the penis and protecting both parties from sexually transmitted disease. Of course, the only thing proven is that oral sex means longer sex in fruit bats. The team concedes a need for further research...

In conclusion, we have documented fellatio in animals that may have functional significance. Of course, adaptive benefits remain unproven until tested, ideally by experimentation, but our study identifies potential avenues to explore if the null hypothesis of no benefit is to be rejected. We believe that ours is the first large scale observational study of oral sex in non-humans, and we extend the interpretation of such behaviour beyond that of 'pleasure giving' into an evolutionary context.

I'm not sure I buy that a behavior that results in a, erm, pleasurable response, really needs any other reason for existing. Although, it is worth noting that this appears to be the first time that fellatio has been documented as a regular part of adult sex outside of humans. Also, the paper contains some truly EXCELLENT quotes that need to be shared. To wit...

During copulation, the pair appeared to move forwards and backwards uninterruptedly and rhythmically.

When copulation was completed, the male licked his penis for several seconds. This self-licking occurred after all of 20 copulations, but was absent after three instances in which intromission failed to occur. Subsequently, the male often groomed himself or licked the inner surface of the tent, yet seldom flew away. Also, the female groomed herself and typically stayed close to her mate.

It is plausible that this female's behavior increased male arousal [22].

There's also a video. Enjoy.

Thanks to Chris Combs at National Geographic Newsfor alerting me to this study.

Thumbnail photo: Allesok [Flickr]