Detalii intime ale sexului cu delfinii dezvaluiti

Multumita unui inflator de penis sub presiune si a organelor genitale aruncate din intreaga SUA, un anatomist a raspuns unei intrebari indelung cautate: cum se potrivesc organele genitale ale delfinilor si a pompoanelor in timpul sexului?

Intr-un cuvant, inot. Intr-o prezentare la intalnirea din acest an a biologiei experimentale de la Chicago, colegul postdoctoral al Universitatii Dalhousie, Dara Orbach, a aratat scanari intime in 3-D ale unei varietati de mamifere marine. Ea a prezentat scanari a doua specii de delfini, precum si porpoize si foca portuare, toate produse folosind organele genitale colectate de la animale care au murit din cauze naturale.

La inceput rosu, complexitatea dragostei de delfini poate parea ridicata. Dar lucrarea lui Orbach este una dintre primele in mai bine de un secol care a reanalizat anatomia sexuala feminina a mamiferelor marine – in acest caz, delfinii si porpoizele. Descoperirile ii vor ajuta pe oamenii de stiinta sa vada cum evolutia a format organele in formele lor prezente.

„Cu anatomia de baza, se considera adesea ca noi oamenii de stiinta avem o idee destul de buna despre structurile mamiferelor si functiile lor, dar acest lucru se dovedeste a nu fi intotdeauna adevarat”, spune Sarah Mesnick, ecologa la Southwest Fisheries Science Center, parte din Serviciul National de Pescuit Marin al Administratiei Nationale Oceanice si Atmosferice a SUA (NOAA).

„Orbach se confrunta cu anatomia asa cum au facut oamenii de stiinta in Age of Discovery, obtinand perspective noi cu fiecare disectie”, a adaugat ea.

„Toate probele de pana acum par sa sugereze ca selectia sexuala pare sa conduca aceasta variatie”, adauga Orbach. “Este un sistem destul de uimitor cu care lucrezi.”

Masurarea organelor genitale

Dar determinarea modului in care evolutia acestor pliuri necesita cunoasterea cu exactitate a modului in care interactioneaza penisurile si vaginele. Penisurile de delfin penetreaza colul uterin in timpul sexului? Cum se aliniaza structurile de pe penis cu pliurile? Si de ce?

Pentru a raspunde la aceste intrebari, Orbach si-a propus sa colecteze tracte de reproducere, solicitand ajutor pentru reteaua nationala de mamifere marine a NOAA, care raspunde atunci cand apar carcasele pe plajele americane. Acum are in jur de 75 de tracturi – excizate in timpul necropsiei pe carcasele – in depozitele de la Mount Holyoke College, unde este asociat de cercetare. „Este ca o zi de nastere [cand] deschideti un pachet ingrozitor”, spune Orbach.

Odata ce Orbach se potriveste cu organele genitale, curata tracturile si apoi le masoara exhaustiv, colectand 50 de tipuri de date pentru un singur vagin. Ea si colegii ei creeaza apoi o matrita din silicon din interiorul vaginului. Separat, umfla penisul pana cand este ridicat folosind un butoi presurizat de apa sarata, apoi il pastreaza intr-un amestec de apa, metanol si formaldehida de gaz.

Apoi, echipa introduce penisul rigid intr-un vagin asortat, le coase pe cele doua si le pastreaza in amestecul de formaldehida. Apoi se trece la Scoala de Medicina Veterinara a Universitatii Tufts, unde radiologul Mauricio Solano le scaneaza in detaliu.

Gaseste cu beneficii

Orbach says that down the line, her research could yield conservation benefits, especially when collecting sperm for artificial insemination. “If you have a biomimetic (artificial but lifelike) vagina, that could trigger the male to produce higher-quality sperm, as opposed to a different device,” she says.

It may be tempting to think that improvements to captive breeding could help Mexico’s vaquita, a porpoise down to its last 30 individuals because of illegal gillnet fishing. However, there are no vaquitas in captivity, much less any that are captively bred. At present, saving the species’s last few members is of much greater concern: An emergency effort to locate, catch, and house remaining vaquitas will kick off in May, but there is no guarantee that the plan will succeed.

When discussing Orbach’s research, she and Mesnick emphasize its more fundamental importance in our understanding of mammal biology.

“Across the animal kingdom, we can see and hear many aspects of mating, such as bright colors of courting males—or their songs—and the ensuing courtship rituals between the sexes. But in species with internal fertilization, there’s just as fascinating a scene that goes on beyond our ability to see it,” said Mesnick. “What happens inside the female’s reproductive tract—the ultimate playing field for sexual selection—is just as important in influencing reproductive success.

“Work like this helps people understand what it means to be a mammal and part of this amazing natural diversity,” she added.

Studying this diversity has been a long, hard process, but as Orbach demonstrates, it’s a fitting—and scientifically satisfying—line of inquiry.