A new study shows that male bats perform oral sex on females to prolong sexual intercourse. The study is the first report of male-to-female oral sex in bats. It complements a previous Chinese study that revealed that female bats perform fellatio on males.
The study "Cunnilingus Apparently Increases Duration of Copulation in the Indian Flying Fox, Pteropus giganteus," was published online by authors Jayabalan Maruthupandian and Ganapathy Marimuthu of Madurai Kamaraj University, in the March issue of the journal PLOS ONE.
The scientists studied a colony consisting of about 420 Indian flying foxes, Pteropus giganteus, one of the largest species of bat in the world, that were roosting on a fig tree (Ficus religiosa) in Nallachampatti, southern India.
According to Live Science, using binoculars and video camera, the researchers witnessed a total of 57 incidents of oral sex and intercourse over a period of 13 months.
The study noted that "Apart from humans, oral sex as foreplay prior to copulation is uncommon in mammals. Another pteropodid bat, Cynopterus sphinx exhibits fellatio with females licking the penis of males during copulation. It appears that bats, especially pteropodids, perform oral sex, either cunnilingus or fellatio, possibly for achieving longer copulation."
Live Science reports oral sex has also been observed among juvenile bonobo who perform it as part of play.
The researchers observed that the male bat first grooms its penis to erection before it approaches the female, who at first withdraws coquettishly while the male follows hers. When the female yields to his advances the male begins to lick her vagina in the act known as cunnilingus. According to the study, the act helps to arouse the female and lubricate her genital tract in preparation for sexual intercourse.
The researchers observed that a session of cunnilingus foreplay typically continued for about 50 seconds, after which the male engages in intercourse with the female for about 10 to 20 seconds before he resumes the act of cunnilingus for 94 to 188 seconds.
The study noted a correlation between the duration of oral sex and copulation.
Marimuthu told LiveScience: "It is possible that prolonged copulation enables the mobility of sperm. Such mobility of sperm increases the chances of conception."
The scientists also speculated that the males might perform cunnilingus on females in order to clean off their competitors’ sperm. This could help to ensure that the sperm of the male performing the act and not that of its rival impregnates the female.
According to the researchers: "In this context, cunnilingus would be maladaptive after mating, as there is a risk of removing the male’s own sperm. Observation at close range is needed to find out whether the male’s tongue enters the vagina or not."
Live Science reports a previous study by researchers at the Guangdong Entomological Institute in Guangzhou, China, that found that short-nosed fruit bat, Cynopterus sphinx, also engages in oral sex routinely. The Chinese study was reportedly the first time fellatio was observed in adult animals other than humans (NB: The author of this article has observed fellatio among adult West African Dwarf Goats).
The researchers concluded that the female Chinese fruit bat performs oral sex on the male to prolong sexual intercourse.
Only fruit bats have been observed to perform male-to-female or female-to-male oral sex. Researchers have not observed oral sex among other species of fruits bats beside Cynopterus sphinx and Pteropus giganteus, but believe it may occur.