Dutch man helps solve mystery of bat species' extremely long penis

Thanks to a Dutchman, researchers have been able to solve the mystery of a bat species’ extremely long penis. Jan Jeucken (72) from Horst and Maas has been filming serotine bats in the attic of the St. Matthias Church in Castenray near Venray for eight years. Thanks to his footage of their mating, researchers have determined what the animal does with its long genitals.

The bat does not use its exceptionally large penis for penetration but as an “arm” during mating, a European team now concluded after studying the images from Castenray and other places.

Jeucken caught the animals mating 93 times in his footage. For the first time, a mammal has been documented that reproduces without penetration during mating, a “baffled” researcher from the University of Lausanne, Switzerland, reported. The male uses his penis to push the female’s tail skin aside. That is followed by a long, silent embrace, during which the sperm is transferred. How exactly that happens needs to be further investigated, Jeucken said.

The serotine bat’s penis is about seven times longer than the length of the female’s vagina. Also notable is that the gland expands in the shape of a heart and becomes much wider than the female’s vagina. That makes penetration impossible, the researchers said.