And now for something completely salacious

November 5, 2009 • 7:57 am

I forgot to proffer this paper of the week before I left. The title alone is a classic: Fellatio by fruit bats prolongs copulation time. 2009. M. Tan, G. Jones, G. Zhu, J. Ye, T. Hong, S. Zhou, S. Zhang, and L. Zhang. PLoS One :4(10): e7595. doi:10.1371/journal.pone.0007595. Be sure to check out the short video at the end of the paper.

You can imagine snickering that went along with writing this abstract:

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.

Seriously, why the licking? Here are the authors’ four theories:

First, genital licking may lubricate the penis or increase penile stimulation, prolonging the duration of copulation. Prolonged copulation might assist sperm transport from the vagina to the oviduct, or stimulate secretions of the pituitary gland in the female [26] and hence increase the likelihood of fertilization. Second, prolonged copulation might be a method of mate-guarding, because the mates would normally segregate after copulation to form unisexual groups which persist throughout the non-breeding season [29]. Third, fellatio may confer bactericidal benefits and assist in the prevention of sexually transmitted diseases (STDs) both to females [30]–[33], and to males that lick their own penis briefly after copulation [34]–[37]. Saliva has a protective repertoire that goes beyond antibacterial activity to include antifungal, antichlamydial, and antiviral properties as well [38]. Finally, genital licking may facilitate the detection and identification of MHC-dependent chemical cues associated with mate choice [39], [40].

15 thoughts on “And now for something completely salacious

  1. “Seriously, why the licking? Here are the authors’ four theories:”

    Theory number five: Because they can.

  2. Way cool! My question is, do insect-eating bats show the same behavior? They can be distinguished from frugivores by the electrophoretic patterns of their salivary proteins (Mammalia, 62: 159-166 (1999)), so a social/behavioral distinction would add a most interesting additional aspect!

  3. I am offended! I thought PLoS was a family journal. Do I have to screen all my scientific journal subscriptions to make sure that little Johnny doesn’t read about fruit bats sucking dicks when he comes home? No more Nature and Science in the living room!

  4. Turns out the annual mtg of the N American Bat Society is just wrapping up today. I understand that this was much-discussed there.

    Further, fruit bats, it seems, are social and roost in the open, where they can be studied. Insect-eating bats are the ones that roost in dark caves, where their social life has been much less studied.

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