Bats Discovered to Have Sex in a Way That’s Similar to Birds

Serotine bat (Eptesicus serotinus)

Mammals typically reproduce through penetrative copulation. However, research suggests an exception: the Serotine bat (Eptesicus serotinus). The size and shape of its erect penis would make penetration impossible, as stated in the journal Current Biology. Consequently, male bats utilize their genitalia differently—as an additional limb, facilitating copulation through the exclusive contact of reproductive organs.

By chance, we had observed that these bats have disproportionately long penises, and we were always wondering ‘how does that work?,” said lead author Nicolas Fasel from the University of Lausanne. “We thought maybe it’s like in the dog where the penis engorges after penetration so that they are locked together, or alternatively maybe they just couldn’t put it inside, but that type of copulation hasn’t been reported in mammals until now.

Little is known about bat copulation, according to the statement. Previous observations provided limited insights, mostly capturing the backs of mating animals. Researchers successfully observed the genitalia of the Eptesicus serotinus bat species during copulation using cameras mounted behind a mesh onto which the bats could climb. The team analyzed 97 pairings.

The researchers did not observe penetration. Instead, they noticed the erectile tissues of the penis enlarging before coming into contact with the female genitalia. During copulation, male bats grasped their partners by the neck, moving their pelvis tentatively until the penis and vulva made contact. Subsequently, they remained stationary, holding the females in a prolonged embrace. The penis served as a tool to expose the female’s genital opening. Fasel stated, “But the males can then use these big penises to overcome the tail membrane and reach the vulva.”

The observed interactions lasted, on average, less than 53 minutes, with one notable outlier lasting nearly 13 hours. The researchers now aim to study bat mating behavior in a natural setting to gain further insights into their reproductive habits.

Featured Image: Wikimedia Commons.