Bat Sex Is Vastly Different from Other Mammals, Researchers Discover

We know a little bit more about bat sexy time.

Originally Published: 
A serotine bat.
Alona Shulenko

In a first, researchers have observed that serotine bats mate using non-penetrative sex, making them the first mammals known to do so.

A serotine bat male’s bulbous-tipped, erect member is seven times longer and wider than its counterpart, making it physically impossible to deposit sperm. Don’t worry: It turns out nature gave it another role. A paper published today in the journal Current Biology divulges the dirty details of Eptesicus serotinus’s sex organ, and how it facilitates what’s known as contact mating.

A serotine bat’s erect penis is seven times longer and wider than its mate’s vagina, ruling out penetrative sex.

Alona Shulenko

Contact mating entails two animals touching sex organs to transfer sperm without inserting the penis into the vulva. Many birds use a version of this method known as the so-called cloacal kiss, the researchers note. The cloaca is an opening beneath the tail base, and sperm transfers from the male’s to the female’s when they touch. After seeing no instance of penetrative sex in serotine bat mating, researchers surmised that they might reproduce in a similar manner.

First author Nicolas Fasel, a biology professor at the University of Lausanne in Switzerland, joined forces with a bat rehabilitation center in Ukraine and a citizen scientist named Jan Jeucken in the Netherlands to better understand this big, upside-down question mark. These two groups contributed 97 bat mating events caught on film — 4 from the rehab center and a whopping 93 from Jeucken, who has recorded hours of activity of bats living in a Dutch church attic. These events lasted about 50 minutes on average, but the longest lasted over 12 hours.

Serotine bats engage in what’s known as contact mating.

Olivier Glaizot

While watching bat sex, Fasel and his team noticed that the male would maneuver his erect penis like a third limb to remove a sheath covering the vulva and simply touch it. Though bats use this covering for flying and capturing insects, it seems to play a reproductive role, too. The researchers that they would need to do further research to confirm DNA sharing.

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