The researchers mimicked the intercourse of dolphins and porpoises with artificial penises and vaginas.
Zoologists from Dalhousie University (Canada) and several US research institutions have studied the physiology of the genitals of three cetacean species. They found that females of two of these three species are able to get rid of the sperm of unsuitable males and thus choose who will father their offspring. A research paper about the research was published in Proceedings of the Royal Society B.
The authors of the study created models of penises and vaginas of bottlenose dolphins (Tursiops truncatus), common dolphins (Delphinus delphis) and porpoises (Phocoena phocoena) based on the genitals removed from the corpses of these animals. For this experiment, individuals who accidentally died in nets off the coast of the USA and Canada were collected. The penises cut off from the corpses were inflated to the size of “live” erect members in the corresponding species and were fixed in this state. Impressions were made from the vaginas of dead females and their models were formed in silicone.
The authors of the study created models of dolphin penises and vaginas. Photo: phys.org
Also in the study, the genitals of common seals (Phoca vitulina) were simulated in a similar way. They belong to another order - pinnipeds. The genitals of their males differ from dolphins by the presence of a bone in them - a baculum.
The researchers placed male genitals in a model of the female vagina of the corresponding species. The position of the genitals relative to each other was selected so that the penis entered the vagina to the maximum depth. The resulting constructs were scanned using a magnetic resonance imaging (MRI) scanner.
Three-dimensional MRI scans have shown that sex has different meanings for different cetacean species. In common dolphins, sexual intercourse unambiguously leads to fertilization. However, in bottlenose dolphins and porpoises, the vagina is designed so that the female, if desired, can remove the seed from it if she does not like the male that left it, and prevent unwanted fertilization. In theory, this means that porpoises and bottlenose dolphins are more resistant to extinction, as they can give birth from the best males.
SVETLANA YASTREBOVA
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