Aptly named vampire squids enjoy long lives in the dark

KIEL, Germany, April 20 (UPI) -- Unlike most soft-bodied cephalopods, which produce and release their eggs all at once (usually right before they die), deep-water vampire squids release their eggs in stages -- a hundred here, a hundred there.

Researchers say their unique reproductive behavior is evidence that vampire squids likely live longer than their shallower peers.

A team of researchers from Germany's Helmholtz Center for Ocean Research recently captured and dissected 43 vampire squids netted off the coast of Southern California. Nearly half of the specimens were found to have already released several hundred eggs, while still having several hundred more immature eggs.

The evidence, researchers say, suggests the rarely studied vampire squid enjoys multiple reproductive cycles. One female squid was found to have released 3,800 eggs, with a remaining reserve of 6,500.

"This reproductive strategy gives advantages to the vampire squid to save energy in the very poor feeding conditions of the deep sea environment," Bahadir Onsoy, a researcher at the Mugla Sitki Kocman University in Turkey, told New Scientist. "In deep sea habitats, the temperature is low, so the metabolism of an animal that lives there is expected to be slow."

Little is known about the vampire squid because it lives at such tremendous ocean depths. Scientists believe the creature is capable of subsisting as much as two miles beneath the ocean's surface.

Researchers say the new evidence of a lengthy and staggered system of reproduction is evidence of the slower pace of life -- and the slower metabolism necessitated by deep-water living. Unlike their relatives closer to the surface who hunt, vampire squids more or less drift, letting the food -- plankton and decaying bits of sinking marine life -- come to them.

"It shows that there's a diversity," lead researcher Henk-Jan Hoving, of the GEOMAR Helmholtz Center, said of the new findings. "And it may indicate that the pace of life is slower than what we know for shallow-water cephalopods, which are known to grow very fast. Age and longevity are important parameters for us to understand how animals live their lives and how their ecosystems work."

The research was published this week in the journal Current Biology.

Previous studies have shown that deep-water octopuses live longer than their peers up above, and also take their time when it comes to reproduction.