One vagina can fit three penises

New study reveals how dolphin Italy fit together

Thanks to a penis pressure pump and genitals flown in from the USA, an anatomist can finally answer the long-standing question: How do the sexual organs of dolphins and porpoises fit together during sex?

In one word: floating. During a presentation at this year's Experimental Biology meeting in Chicago, PhD scientist Dara Orbach from Dalhousie University showed intimate 3D scans of some marine mammals. She presented scans of two species of dolphins, as well as common porpoises and seals, all of which showed the genitals of these animals. The specimens had died naturally.

At first glance, the subtleties of dolphin love seem piquant. But Orbach's work is the first in over a hundred years to analyze the female sex anatomy of marine mammals - in this case dolphins and porpoises. Their results will also help scientists understand how evolution brought organs into their current shape.

“When it comes to basic anatomy, it is often assumed that we scientists have a fairly good understanding of the structures and functions of mammals. But that doesn't always turn out to be correct, ”says Sarah Mesnick, an ecologist at the Southwest Fisheries Science Center, part of the U.S. National Marine Fisheries Service. National Oceanic and Atmospheric Administration (NOAA) is.

"Orbach experiences anatomy just like scientists did in the Age of Discovery and gains new knowledge with every dissection," she adds.

There is still a lot to discover in the field of sexual anatomy. Accurate studies of how the genitals fit together have so far mostly been limited to small insects, spiders, and lizards (even if at least one MRI study has looked at humans). For a long time there was a gap in science in the field of study of the female genitalia. This was not least due to the fact that it was comparatively easy to examine penises and for a long time it was held to the assumption that vaginas differ less than penises across the various types.

The study from March 2017, on which Orsbach and Mesnick co-wrote, shows, however, that the vaginas of marine mammals are characterized by an astonishing variety of inner lobes and folds. For example, the female sex organ of the bottlenose dolphin has a single fold, while that of the common porpoise has about 13 of them.

“The lobes, folds and dead ends of the female reproductive tract could pose a challenge to the male's sperm or competing male rivals. The sperm must pass through this structure in order to reach the egg, ”explains Mesnick in an email.

"So far, everything indicates that this variation is controlled by sexual selection," Orbach adds. "That's a pretty amazing system that is being used."