As the one mammals that may fly, bats are the oddballs of the mammalian world. However serotine bats stand out for one more, manifestly apparent purpose — when erect, a male’s penis can swell to nearly 1 / 4 of its physique size. How these bats use their humongous genitals to mate — with out penetration — is a technique by no means seen in a mammal earlier than, researchers report within the Nov. 20 Present Biology.
At greater than 16 millimeters when erect, the penis of male serotine bats (Eptesicus serotinus) has no likelihood of becoming inside the feminine’s roughly 2-millimeter-long vagina, a discrepancy that prompted biologist Nicolas Fasel to marvel how these bats go about getting it on. Movies collected on the Ukrainian Bat Rehabilitation Middle in Kharkiv from 2018 to 2021 and the attic of St. Matthias Church in Castenray, Netherlands, from 2016 to 2022 revealed the reply. With footage, taken from beneath the bats, “we may see truly what was taking place,” says Fasel of the College of Lausanne in Switzerland.
As a substitute of inserting its penis into the vagina, a male makes use of it to maneuver apart a membrane overlaying the feminine’s genitals after which presses the penis towards the feminine’s vulva and holds it there, typically for just below an hour. In a single remark, the habits lasted greater than 12 hours.
As soon as the deed was carried out, the fur across the feminine’s vulva appeared moist, which Fasel and colleagues suspect is because of semen. Different scientists instructed Fasel the moist spots look just like these by which they’ve discovered semen after mating in different bat species, he says. These observations counsel the serotine bats are mating with out penetration, a widespread follow in birds however one by no means noticed in a mammal earlier than (SN: 1/16/09).
“I believe it’s tremendous attention-grabbing as a result of it kind of brings up a unique perform for a penis” apart from penetration, says Patricia Brennan, an evolutionary biologist at Mount Holyoke School in South Hadley, Mass. “It doesn’t shock me that it is a bat as a result of bats have a number of the craziest reproductive methods in mammals,” comparable to females with the ability to retailer sperm for six months or males having spines on their penises.
Fasel agrees. Amongst mammals, bats “simply should be the weirdos of the group.”
