"The male has an enormous, long penis—but it's incredibly narrow—with which he inserts packages of sperm directly into the female's mantle," he said. "The heads of those packages of sperm explode and individually fertilize the eggs within the mantle itself.
"That process is confirmed" in Teuthowenia, O'Shea said. "It's obvious that she's brooding those eggs within the mantle, and I don't think it's a big stretch to extrapolate that to the colossal squid."
Glowing Babies Blacked Out
O'Shea also speculates that, as the thousands of baby colossal squid grow inside their mother, they develop the light-emitting organs called photophores, which were confirmed during the April dissection. That could pose a risk in the dark depths where colossal squid live—as far down as 6,500 feet (1,980 meters).
"She's just a sitting duck down there," O'Shea said. "You don't want to be lit up like a giant crystal chandelier."
The squid's natural predator, the sperm whale, would relish a meal of "nutritious, egg-brooding colossal squid," he added.
But, in an apparent evolutionary defense, the colossal squid's mantle is lined with an opaque, deep-red membrane, which would block the light of her babies' photophores.
(See "Colossal Squid Has Glowing 'Cloaking Device,' Huge Eyes" [May 1, 2008].)
Previous research has proposed that colossal squid lay eggs. But O'Shea speculates that the giants give birth to live young.
"She's holding onto them until they're fully functional juveniles, then spitting them out at great depth. Then she is going to die," he said. Though the life cycles of deep-sea squid are not fully known, better-studied squid species are known to die shortly after birth.
Fresh from dissection, the colossal squid is now on display at the Museum of New Zealand in Wellington.
Chris Paulin is the natural environment projects officer at the Museum of New Zealand in Wellington, where the colossal squid is now on display. He said growth rings seen in another species, the giant squid, indicate that giant squid live for just a few years.
"It's quite likely that this colossal squid—assuming it has a similar life history to the giant squid—may have reached this size in three or four years."
"A Hell of a Lot of Squid"
Confirmation of the colossal squid's habits, though, will come only from "more specimens and building our knowledge base ," Paulin said.
Given the recent boom in commercial fishing for toothfish (sold as "sea bass") in Antarctic seas, more colossal squid specimens should turn up in the next few years, he said—particularly if New Zealand mandates that all accidentally caught animals be brought back to port along with the intended catch. Colossal squid are thought to frequent the same deep Antarctic waters as toothfish, apparently a favorite colossal squid food.
(See sea bass fishing photos.)
Colossal squid could well be very numerous, Paulin said.
"Put it this way: A sperm whale has to eat about 2,200 pounds [1,000 kilograms] of food a day, and the colossal squid makes up about 75 percent of that.
"I don't know how many sperm whales there are in Antarctica, but that's a hell of a lot of squid."
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