Artículo de New York TimesWhen Giant Squids Mate, It's a Stab in the Dark By WILLIAM J. BROAD
Published: October 21, 1997
Little is known of what lives in the depths of the sea, much less how the creatures of darkness live and die, hunt and eat, play and reproduce. Nevertheless, two scientists in Australia have managed to shed light on the sex life of the giant squid, the most famous of legendary sea monsters.
The evidence suggests that the male is a rather violent lover, grabbing the female in the darkness and injecting sperm into her skin at high pressure, creating a small wound. Later, the sperm is used to fertilize eggs.
Rough sex is not unknown in the animal kingdom. Females of several species eat their mates. Some garden snails use darts in reproduction.
But the discovery of surly conduct in the giant squid -- the world's largest known invertebrate, a colossus up to 70 feet long that has haunted man's seafaring past like a bad dream -- only reinforces the idea that nature does whatever it takes to promote the cause of procreation.
''I'm still surprised,'' Dr. Mark D. Norman, one of the Australian scientists, said in an interview. ''I think it's pretty bizarre behavior.''
The giant squid is often known by its genus name, Architeuthis (pronounced ark-e-TOOTH-iss), Greek for chief squid. In lore and legend, fact and fiction, the animal has been encountered by humans for centuries. Only in recent decades, however, has it emerged as an object of scientific study.
The new discovery was made when Dr. Norman and Dr. Chung-Cheng Lu of the Museum of Victoria and the Zoology Department of the University of Melbourne were recently able to study a giant female squid. It had been caught by fishermen working off Tasmania at depths of up to one kilometer, or six-tenths of a mile, and was dead when the scientists examined it.
The captured female was about 50 feet long. In a first, it was found to contain sperm, the Australian scientists report in the current issue of Nature, the British scientific weekly.
In the report, the scientists note that some 20 female giant squid have been examined over the decades, but none have ever been found to be inseminated. Usually dead by the time they reach the surface of the sea, such giants typically wash ashore or are captured accidentally by fishermen trawling at increasingly great depths.
Scrutiny of these previous finds has shown that female giant squid bear no special receptacles to hold sperm, unlike some species of squid and octopi that may store semen for months prior to egg fertilization.
All squid have 10 arms. The Australian scientists found that one of the forward arms of the captured female bore a small, shallow wound, from which a cord of immature sperm protruded. Inside the arm, they found the remains of three spermatophores, or protective sperm packages, each a few inches long and filled with millions of sperm.
The squid's skin had been partly torn away on the other forward arm. Beneath the wound were more embedded spermatophores.
On both arms, the spermatophores were found to be in similar positions, ''suggesting deliberate placement,'' the scientists said in the Nature report.
''It seems that male giant squids may use their muscular elongate penis to 'inject' sperm packages under pressure directly into the arms of females,'' the scientists said. Researchers have found that the penises of giant squid can measure up to three feet in length.
The stockpiling of semen under the skin of females is known to occur in a few species of small squid. There, spermatophores are stored in healed elongate wounds on the arms or the mantle, the flexible cloak that aids swimming and covers most of the squid's delicate body parts.
Scientists speculate that males of such species may use their beak or sharp hooks on their tentacles to cut the elongated wounds, and later fill the wounds with sperm.
The cut found on the giant squid female, however, was much smaller than these lengthy gashes, leading the Australian scientists to conclude that the sperm may have been pumped in ''under hydraulic pressure,'' much as a doctor's syringe injects medicine.
The scientists note in their article that the spermatophores of the giant squid are enveloped in a gelatinous coating, which is unreported for any other species of squid, octopus or cuttlefish. This coating, the scientists speculate, may act as a lubricant to aid injection into a female's skin.
They also note that a male giant squid caught off Norway in the 1950's was found to have spermatophores embedded in several of its arms and its mantle. Another male may have injected the spermatophores while attempting to impregnate a female in a case of mistaken identity, the scientists say.
Alternatively, they suggest, the male may have ''literally shot himself in the foot.''
Dr. Clyde F. E. Roper, curator of mollusks and a squid expert at the National Museum of Natural History at the Smithsonian Institution, said the Australian report was intriguing. But only further studies, he said, and further landings of inseminated females, would confirm whether the inferred conduct in fact takes place.
''You have to be very, very careful about speculating on the behavior'' of animals based on evidence from their remains, Dr. Roper said in an interview. He added, however, that the proposed action ''is really intriguing and not implausible.''
In their Nature report, the Australian scientists note that the mated female was immature, her ovary holding hundreds of thousands of undeveloped eggs.
The scientists say this suggests that giant squid may be able to store sperm for a long time, perhaps aiding reproduction in a dark realm where encounters between males and females may be infrequent at best.
As for fertilization of eggs, scientists agree that nothing is known about the habits of the giant squid. In fact, there are no reports on how females of any of the species of skin-storing squid gain access to the stockpiled sperm.
The beak of a squid's mouth or the suckers of its tentacles may be used to peel open the skin that covers the spermatophores, the Australian scientists say, or perhaps the sperm may migrate to the surface upon receiving hormonal or chemical cues.
''Alternatively,'' the scientists say, ''the female's skin might degrade on spawning, exposing the embedded sperm.'' Spawning is when a female lays her eggs.
What happens next is also unknown. Eggs and sperm somehow become mixed together and are probably encased by the female in a huge gelatinous mass, as all other known ocean squid are thought to do. Whether this mass of fertilized eggs drifts in the sea or becomes attached to the bottom is also a mystery.
Somehow, the ritual of reproduction is completed and the progeny grow up to their gargantuan adult size, as has happened in the deep sea among generations of giant squid for millions of years.
''I think it's nice that there are these mythical creatures down there that we know so little about,'' Dr. Norman said. ''There's so much that's still undiscovered.''