Sea animal’s disposable penis, bizarre sex life bared

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PARIS—Scientists reported Wednesday on the bizarre sex life of a sea slug that discards its penis after copulation. Then grows a new one.

“No other animal is known to repeatedly copulate using such ‘disposable penis’,” Japanese biologists wrote in the Royal Society journal Biology Letters, describing the behavior as “extremely peculiar”.

Dubbed Chromodoris reticulata in Latin, the red-and-white slug — technically a shell-less mollusk — inhabits warms waters in Southeast Asia.

The critter needs 24 hours between couplings to unroll an internally coiled and compressed juvenile penis to replace the used, external bit, the scientists found.

It can repeat this feat at least three times.

The human thumb-sized slug is a hermaphrodite, meaning it has both male and female sexual organs.

The animals perform dual sexual roles during copulation. They give sperm to a mating partner while simultaneously receiving sperm, which they store for later insemination.

The team observed copulation between sea slugs that they had captured during scuba dives and held in a tank.

After each coupling, which lasted between dozens of seconds and a few minutes, every slug discarded its penis — a thread-like organ that it projects from its side into a partner’s vagina.

The team also examined the microscopic structure and function of the male organs — observing an internal spiral structure they believe grows into a replacement penis.

“We propose that the tissue at the spiral part of the penis is compressed and undifferentiated, gradually differentiating into the ‘next penis’,” the team wrote.

“It may need approximately a day for the spiral structure to be ready for copulation.”

In another revelation about the sea slug’s sex life, the scientists found its penis was covered with spines — and suggested these may be used to remove the sperm of previous partners being held in store by their mate.

The spines are backward-pointing, making it difficult to withdraw the penis after copulation. This may explain the organ’s disposable nature.

“Chromodoris reticulata may compensate for the short-term cost of decreased reproductive opportunities caused by the loss of a penis with the reproductive advantage gained by sperm displacement,” wrote the study authors.

Various animals are known to discard parts of their body, such as the gecko which sheds its tail.

Few, though, are willing to part with their penis, the team noted with clinical understatement.

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  • kilabot

    in humans they’re called transsexual. perverts for short. 

    No to nature violation! 
    No to perversion!

    • KpTUL

      Another loose thread here. Blog something that make sense and stop polishing your naivete in the web.

    • tamumd

      Hahahaha..and now you’re accusing sea slugs as perverts? lol i don’t think a slug has a capacity to comprehend what you’re accusing it to be. You gotta love the brain of a gullible, Taliban-like religiot.

      • ryan andres

        Nice! You hit that asswipe pretty hard bro

    • ryan andres

      Maliit siguro bird mo kaya kung maka-no ka eh wagas

  • w33k3nd3r

    Buti pa sila may sex life.

  • speedstream2

    In a world where there’s lots of disposable items, a disposable but “regrowable” organ is simply amazing. But who wants to be sea slug? :-)

  • ryan andres

    “Sea animal’s disposable penis, bizarre sex life bared”

    – sounds like Miriam Santiago writing a headline to expose Pinky Lacson…

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