An “extremely long penis” when erect. We’re not talking about your boyfriend’s, but a particularly well-hung species of bat. It raised many questions in the scientific community before a Dutch retiree solved the mystery.
Its observations allowed a team of European researchers to conclude that this species, the common serotina, does not use its organ to penetrate the female’s genitals, but as a sort of “copulative arm”, according to a study published in Current Biology. This is the first time that a mammal has been recorded with the ability to reproduce without the introduction of its genital appendage.
Seven times larger than the female organ
The Common Serotina, which has a wingspan of more than 35 centimeters, is a widespread species in the forests of Europe and Asia. Biologist Nicolas Fasel, a researcher at the Swiss University of Lausanne, told AFP that his team had long noticed that the animal had “an extremely long penis when it is erect.”
A size seven times longer than the female’s organ could accommodate. Above all, the end of his erect penis takes the shape of a heart, also seven times too big to allow penetration. Characteristics that make classic copulation “impossible”, according to Nicolas Fasel.
A passionate retiree
The mystery was all the greater as bat mating is difficult to observe. The solution arrived via an email, the first word of which was “Penis”, followed by something in Dutch, and the word “Eptesicus”, namely the scientific name of the species. The latter caught the attention of Professor Fasel, who by watching the video attached to the email understood that he “had his answer”.
The sender, Jan Jeucken, is a retiree with no scientific training living in the small village of Castenray in the south of the Netherlands. Having taken interest in a population of Serotines living in the attic of the local church, he installed cameras recording their activity. A “passion making him the ideal person” to understand their behavior, according to Professor Fasel, who included the retiree in the list of authors of the study published this week.
A still embrace
The researchers analyzed 93 matings in the church, filmed through a grid on which the bats clung. The female Serotine has a large membrane connecting the tail to her elbows that she can use to protect her genitals. During mating, the male grabs the female by the nape of the neck and uses his long penis to spread this membrane and reach the entrance to the genital tract.
What follows is a long, immobile embrace, called “contact mating,” which allows the transfer of the male’s sperm. This form of reproduction without penetration, also called “cloacal kissing”, is common in birds, but has never before been observed in a mammal. The embrace can last forever in the Serotine bat, with an average duration of 53 minutes, and a recorded record of 13 hours.
According to Professor Fasel, the female could use her extremely long cervix to store sperm from different males for months, before choosing one to procreate. It is possible that other species of bats reproduce this way, adds the researcher, who supposes that more research on the subject could see the emergence of “many other species with strange penises”.