The male sex organs of the animal kingdom come in all shapes and sizes from some that look like a bottle opener to genital stingers. For mammals, penetrative sex with a penis is needed to successfully mate. However, scientists have documented the first non-penetrative sex ever seen in a mammal. The mating technique was observed in the serotine bat (Eptesicus serotinus) and it is described in a study published November 20 in the journal Current Biology.
The mysteries of bat sex
Serotine bats are quite common in Europe and Asia, but the intricacies of bat sex remain elusive. Most previous observations of bats mating have only offered a glimpse of the backs of mating pairs. But in the new study, a team from the University of Lausanne in Switzerland and a bat rehabilitation center in Ukraine got lucky.
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“By chance, we had observed that these bats have disproportionately long penises, and we were always wondering ‘how does that work?’,” study co-author and University of Lausanne evolutionary biologist Nicolas Fasel said in a statement. “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.”
The team placed cameras behind a grid that the bats could climb hoping to get footage of their genitals and mating from one side of the grid. They found that bats’ penises are roughly seven times longer than their partners’ vaginas. Each has a “heart-shaped” head that is also seven times wider than the common bat vaginal opening. This size and shape would make penetration after an erection impossible. The study shows that instead of functioning as a penetrative organ, the penis is more like an extra arm. It pushes the female’s tail sheath out of the way to…
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