Swiss research reveals the secret of a broad-winged bat’s enormous penis

The research team from the University of Lausanne and the Natural History Museum Naturéum in Lausanne has shown for the first time that a mammal has the ability to reproduce without inserting the penis, according to the study published on Monday evening in the scientific journal ‘Current Biology’. .

The broad-winged bat (Eptesicus serotinus) is a large insectivorous bat found in Europe, the Middle East and Asia. From head to torso, the animal, which weighs 15 to 30 grams, has a maximum length of about 80 millimeters and an extra tail that is a maximum of 57 millimeters long. The wingspan is a maximum of 38 centimeters.

His team had long noticed that the animal had “an extremely long erect penis,” biologist Nicolas Fasel of the University of Lausanne told the AFP news agency.

Compared to the size of a woman’s vagina, the erect penis is seven times longer and seven times wider at the heart-shaped tip. This makes a classic connection impossible, Fasel emphasizes. Because mating is difficult to observe in nocturnal bats, the researchers were faced with a puzzle.

“So we wanted to know how the coupling works,” Fasel told the Dutch science magazine Scientias. “We thought it might be like dogs, where the penis swells after penetration and the animals then cling to each other. Another theory was that there was no penetration.” However, this type of copulation, which is common in birds, has not yet been observed in mammals. “That has now changed,” notes Fasel.

To understand how these bats mate, the biologists observed their mating behavior in different locations: in the attic of a church in the Netherlands, in temporary captivity in a rehabilitation center in Ukraine, and in the mines of Baulmes in Switzerland, such as the university. Lausanne writes in a message.

The breakthrough to solve the mystery came via email from the Netherlands: pensioner Jan Jeucken had become interested in a group of broad-winged bats living in the attic of the village church and recording their activities with specially installed cameras. 93 of the 97 observed matings took place there.

When he saw the video attached to Jeucken’s email, he immediately realized he “had the answer,” biologist Fasel said.

According to observations, the male places the female on his back, as many other mammals do, and uses his long penis as an arm to bypass the female’s tail membrane. “Bats use their tail membranes to fly and catch insects. The females also use it to cover their genitals and protect themselves from the males,” Fasel explains. “The males, on the other hand, can use their large penis to push away the tail membrane and reach the vulva.”

This is followed by a long, motionless clasp, known as ‘contact mating’. The male’s sperm is transferred. In the broad-winged bat, this “contact mating” can last a long time: from 53 minutes to almost 13 hours. (mr/sda/afp)