For the first time in the scientific community, a mammal has been documented to engage in mating behavior without penetration. This groundbreaking discovery was made by researchers at the University of Lausanne, Switzerland, who published their findings in Current Biology. The study focused on the serotine bat and revealed that the male bats use their oversized penises to maintain contact during mating instead of penetration.

Nicolas Fasel, lead author of the study, stated that they think this type of copulation is similar to what occurs in dogs where the penis becomes engorged and sticks, or perhaps they simply could not insert it. However, this type of mating had not been previously described in mammals until now.

The researchers observed 97 pairings from two different locations and analyzed images taken from cameras placed behind a grate that allowed them to climb onto. They also noted that the female’s abdomen appeared moist after copulation, suggesting semen transfer. However, more studies are needed to confirm sperm transfer and deepen our understanding of this unique mating behavior.

In addition to studying mating behavior in serotine bats, researchers also characterized their genitalia morphology by measuring erect penises and performing necropsies on deceased specimens. When erect, male serotine bats’ penises are about seven times longer and seven times wider than females’ vaginas of the same species. This finding raises new questions about other bat species and their reproductive practices. Further research is needed to understand how bats mate in natural contexts and how their genitalia morphology affects bonding behavior.

This study provides insight into never-before-documented mating behavior in mammals and sheds light on serotine bats’ reproductive practices while raising new questions about other bat species’ reproductive behaviors.