CEPHALOPODS

A Penis As Big As His Body

Scientists didn’t have a good idea about how the cephalopods – octopuses, squids, and cuttlefish – of the deep get in on. The problem is in the way the body is set up. Most of what appears to be the body and head of, say a squid, is actually a hood, called a mantle. They use the mantle both to move through the water and to force water across their gills by forcing water out of the bottom, like jet propulsion. But that also means that their sex organs are protected inside.

That makes a pretty big problem for the dudes. How do they get their sperm past the female’s mantle? If they spray some sperm up in there, it won’t stick around long since it will get washed out as she propels all that seawater through her mantle.

Shallow-water dwelling cephalopods have figured out a solution. They have short penises which produce small “packets” of sperm called spermatophores. One of their eight eponymous limbs is actually modified to transfer this sperm into the proper receptacle on the female cephalopod.

But scientists still had no good idea how their deeper-dwelling cousins got the job done. Deep-water male squid are known to use a more primitive method, which involves somehow injecting their sperm into the female’s body. But how? “Obviously a strongly elongated penis is the solution,” says Dr Arkhipkin of the Falkland Islands Government Fisheries Department, who explains how he and his colleagues made the discovery:

“The mature male squid was caught during a deep-water research cruise on the Patagonian slope. We took the animal from the catch, and it was moribund with arms and tentacles still moving, and chromatophores on the skin contracting and expanding,” he told the BBC.

“When the mantle of the squid was opened for maturity assessment, we witnessed an unusual event.

“The penis of the squid, which had extended only slightly over the mantle margin, suddenly started to erect, and elongated quickly to 67cm total length, almost the same length as the whole animal.”

…

The squid uses its lengthy organ to reach into the body of the female, and it then injects the sperm directly to prevent it being washed away.

How the sperm injected into a female’s body then reaches her reproductive organs remains a mystery.

Male with erect penis and ejaculated spermatophores on table (penis is white tubular structure in lower half of the picture).

I’m not really sure what the moral of this story is. But next time someone calls me a squidfucker, I will take it as a compliment.

Signing off, polyps. Remember! You don’t know Dick.
…But don’t worry. We’re here to help you.


Information and photo from BBC Earth News.

Dick Feynman (@feynmandick) is a Los Angeles-based scientist, specializing in diluting scientific research findings into tasty, bite-sized bacon-flavored snacks for the unwashed masses.