It had not been observed until now in mammals
Video cameras in the Netherlands and Ukraine reveal that this elusive bat with a disproportionately large penis mates in a way never seen in mammals: by contact and not by penetration.
Two indiscreet cameras – one installed in an animal rehabilitation center in Ukraine and another in a church in the Netherlands – have recorded the elusive garden bats in the middle of a sexual encounter. Some recordings that have perplexed ethologists because they have revealed behavior that until now had never been seen in mammals: They mate without penetrating the female, according to a study published this Monday in the magazine Current Biology.
It is common for mammals to practice penetrative sex, but scientists have discovered an exception in this species of bat called hortelano or serotino (Eptesicus serotinus). According to the researchers, It is the first time that copulation without penetration has been documented in a mammal.
As you have seen in the videos, these animals they mate by contact, something similar to what in birds is called cloacal kissing or opposition (the male places himself on the female and transfers the sperm to her using the same duct he uses to excrete). In a similar way, male bats of this species use their penis – which is seven times longer than the female’s vagina – as a kind of extra arm to facilitate copulation, but not as an organ of penetration.
In addition to being seven times longer than their partners’ vaginas, their penises have a heart-shaped head that is seven times wider than the vaginal opening. Both their size and shape would therefore make penetration after erection impossible, and researchers have now documented that they are used to facilitate such contact mating.
“By chance, We had observed that these bats have disproportionately long penises and we always wondered ‘how do they work?’‘. We think that perhaps it happens like with the dog, whose penis swells after penetration, or that they simply could not insert it into the vagina, but this type of copulation had not been seen in mammals until now,” he explained in a statement from press Nicolas Fasel, lead author of the study and researcher at the University of Lausanne.
This is a new case that shows that you only have to observe the behavior of animals to be surprised and see how much is unknown about other mammals. In fact, Until now, very little was known about how bats reproduce.. Most previous observations of mating couples had been made from behind, with their backs turned. But on this occasion they were able to observe the genitals of the bats during their sexual encounters using images of cameras placed behind a grate that the bats could climb.
Fasel collaborates with a bat rehabilitation center in Ukraine that opportunistically films mating couples, and with a bat hobbyist, a citizen scientist named Jan Jeucker, who filmed hours of the life of a gardening bat in the attic of a church in the Netherlands. In total, the team was able to analyze 97 mating events: 93 recorded in the Dutch church and four in the Ukrainian bat rehabilitation center.
On average, these sexual encounters lasted less than 53 minutes, but the longest lasted 12.7 hours. At no time did they notice that the erectile tissues of the penis enlarged before making contact with the vulva. During mating, male bats grabbed their partners by the neck and moved their pelvises (and their fully erect penises) until they made contact with the female’s vulva, at which point they remained still and embraced the female in a very long embrace. hug.
After copulation, they noted that the females’ abdomens appeared moist, suggesting the presence of semen, but the scientists say they need more research to confirm that sperm was transferred, as they believe.
If they know the length and shape of bat penises it is because in previous studies They have investigated their genitals, capturing live specimens to measure their erect penises, and performing necropsies. in bats that have died in rehabilitation centers. They are also known to have unusually long cervixes (the part that connects the uterus to the vagina), which could help females select and store sperm.
One hypothesis is that bats may have developed penises that are disproportionately large with respect to their overall body size to remove tail membranes from females, which they can use to avoid sexual relations. “Bats use their tail membranes to fly and capture insects, and females also use them to cover their underparts and protect themselves from males, but males can use these large penises to overcome the tail membrane and reach the vulva,” says Fasel.
Now they want to continue investigating the sexual behavior of bats in more natural environments, while also studying the morphology of the penis and how other species mate.