We're going to discuss an animal that is near and dear to my heart: squids.
There's been a bit of a question mark lurking over the mating habits of sexually-active squids. All squids possess a mantle, which comprises the bulk of their body, and is used for a variety of purposes: by contracting and expanding it, they can send water through the hyponome to move via jet propulsion, ventilate it in order to breathe, and its also where the excretory and sexual organs are kept. And therein lies the challenge: How can a female squid store a deposit of sperm when the ebb and flow of water passing through the mantle will likely sweep it away?
Shallow-water male squids have developed a special apparatus called a hectocotylus to transfer and deposit packets of sperm inside the female's mantle. Deep-sea squid, however, do not have a hectocotylus and instead inject the sperm right under the female's skin. The only question left is: How do they do it?
Dr. Alexander Arkhipkin and his colleagues solved this riddle after capturing a mature male specimen of Onykia ingens on the Patagonian slope near the Falkland Islands. In its agitation, the squid revealed a surprising organ.
"When the mantle of the squid was opened for maturity assessment, we witnessed an unusual event," explains Arkhipkin. "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."
This allows deep sea squids the ability to forcefully inject spermatophores within the female squid mantle cavity, while still maintaining a safe distance away from a potential predator. Sounds like a win-win scenario to me.