A groundbreaking study published in Current Biology has unveiled a new form of mating behavior in mammals – specifically in the serotine bat. The penises of bats are about seven times longer than the vaginas of their partners and have a head-heart shaped seven times wider than the vaginal opening, making penetration impossible. Instead of functioning as a penetration organ, male bats use their oversized penises to move the female’s tail sheath away and maintain contact mating.
Nicolas Fasel, from the University of Lausanne, Switzerland, and lead author of the study stated, “We think that perhaps it is like in the dog, in which the penis becomes engorged so that it becomes stuck, or perhaps they simply could not insert it, but that type of copulation had not been described in mammals until now.”
The study observed 97 pairings from the Dutch church and Ukrainian center using cameras placed behind a grate that they could climb onto. The researchers analyzed genitals during copulation and found that the female’s abdomen appeared moist after copulation, suggesting semen transfer. However, more studies are needed to confirm sperm transfer.
The researchers also characterized serotine bat genitalia by measuring erect penises of live specimens and performing necropsies on those that died. When erect, these penises are about seven times longer and seven times wider than female vaginas. The study plans to continue studying mating behavior in natural contexts and analyze penis morphology and bonding behavior in other bat species.
In summary, this study has shed light on never-before-documented mating behavior in mammals, revealing insights into serotine bat reproductive practices and raising new questions about other bat species. Further research is needed to deepen our understanding of bat mating behavior.