In time for Halloween, Treehugger guides us:

New research published in the online journal PLoS ONE demonstrates for the first time that a non-human adult animal species regularly engages in oral sex behavior. While the behavior has been seen in juvenile animals before, this is the first time it has been observed in adult animals.

Though it has been observed previously in bonobos (both heterosexually and homosexually), this behavior generally has been confined to juvenile animals, the authors of the new study note. The field research, which was conducted in Guangzhou City, China, reveals that in the case of the greater short-nosed fruit bat (Cynopterus sphinx) female species-on-male species oral sex now has been documented as a regular occurrence. Scientists observed that in instances where oral sex was performed, copulation time increased.

Or how something the Vatican regards as intrinsically evil is actually hardwired to enable something intrinsically good. The details are somewhat alien to human experience:

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.

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