You may already know that fruit bats are among the few species besides humans to engage in fellatio, but new observations confirm they practice cunnilingus, as well. And yes – there's video evidence.
Back in 2009, researchers observed extensive evidence of fellatio among short-nosed fruit bats, and concluded that in 70 percent of sexual encounters, the female bat would lick the shaft of her partner's penis. Now, newly published research shows that male members of another fruit bat species – the Indian flying fox – regularly engage in cunnilingus.
Ed Yong gives a tidy summary over at Phenomena:
In the summers of 2010 and 2011, Jayabalan Maruthupandian and Ganapathy Marimuthu clocked 1,170 hours watching a colony of flying foxes near a south Indian village. They saw the bats mate 57 times, most of which involved a brief amount of penetration bracketed by longer bouts of cunnilingus. The male would fluff up his penis and sidle over to a nearby female. He craned his neck over and licked her vagina for up to a minute, mounted her for around 15 seconds, and returned to 2.5 minutes of cunnilingus.
The actual sex isn’t exactly lengthy, but as in the short-nosed fruit bat, the flying foxes prolong their liaisons with oral sex. The males bought themselves an extra 2 seconds of penetration if they spent an extra 15 seconds of cunnilingus beforehand.
Those extra couple of seconds could offer males more time to fertilize their chosen mate. That might not sound like a lot of time, but when your bouts of copulation last between 10 and 20 seconds, a couple extra ticks of the second hand could make all the difference in the world. (For reference, the earlier study on fellatio in short-nosed fruit bats found sexual encounters that involved oral stimulation lasted 100 seconds longer, on average, than those that didn't.)
It could also have something to do with hygiene; it's conceivable that bats would engage in oral sex to clear away potentially infectious bacteria and fungi.
Maruthupandian and Marimuthu hypothesize that cunnilingus could serve as a way for males to remove the sperm of previous partners, though that raises technical questions over why a male bat would engage in oral sex after having mated, himself.
"In this context," the researchers write in the latest issue of PLoS ONE, "cunnilingus would be maladaptive after mating as there is a risk of removing the male’s own sperm."
"Observation at close-range," they continue "is needed to find out whether the male’s tongue enters the vagina or not." You know. For science.
Ed Yong has more details on this, and previous, research on bats and oral sex at Phenomena. Or check out the research for yourself, free of charge, over at PLoS ONE.