April 2, 2008

Octopuses Have Complicated Love Lives

Researchers from University of California, Berkeley, reported Monday that octopuses have love lives far more complex than previously known, and that the animals exhibit rather sophisticated behavior such as flirting, holding hands and even displaying fits of jealousy.

Octopuses are well studied in captivity, but their behavior in the wild is less understood but as the animals are shy and often nocturnal. During the new research, graduate student Christine Huffard examined the Abdopus Aculeatus, an octopus with a tan body the size of a small orange and 10 inch arms, while snorkeling in the waters off Indonesia.

"Each day in the water, we learned something new about octopus behavior, probably like what ornithologists must have gone through after the invention of binoculars," said Huffard, now at the Monterey Bay Aquarium Research Institute in Moss Bay, California, during an interview with Reuters.

"We quickly realized that Abdopus aculeatus broke all the rules, doing the near opposite of every hypothesis we'd formed based on aquarium studies."

The team observed male cephalopods guarding their mates' dens for days at a time, keeping rivals at bay or even strangling them if they got too close. Small males would often sneak up on their potential mates, swimming low to the ground in feminine fashion so as not to display their "male" brown stripes.

Surprisingly, the scientists found that size did indeed matter, albeit differently than for humans.

"If you're going to spend time guarding a female, you want to go for the biggest female you can find because she's going to produce more eggs," biology professor Roy Caldwell told Reuters. "It's basically an investment strategy."

Caldwell believes the behavior observed in the Abdopus aculeatus is common to many of the nearly 300 species of octopus.

The octopuses typically mate several times a day once they reach sexual maturity. Males use a specially designed arm to deposit a sperm packet into the female, who then lays tens of thousands of eggs after retiring to her den. Both parents die within a few months of mating, leaving the newborns to take care of themselves.

The research was published in the journal Marine Biology.  An abstract of the report can be viewed at http://www.springerlink.com/content/2x868ll35802146q/.


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