April 3, 2008—A male octopus (right) deposits a sperm packet into a female in this photo taken during a field study and released on Monday.

The study found that wild octopuses engage in "jealous murders," gender bending, and once-in-a-lifetime sex—unlike their seemingly shy, unromantic captive brethren.

The University of California, Berkeley, scientists watched the baseball-size Abdopus aculeatus octopus species off Indonesia for several weeks and published their findings recently in the journal Marine Biology.

The team witnessed picky, macho males carefully select mates. The octopuses would then guard their newly domesticated digs jealously—occasionally going so far as to use their 8- to 10-inch (20- to 25-centimeter) tentacles to strangle romantic rivals to death.

"This is not a unique species of octopus, which suggests others behave this way," said Berkeley biologist Roy Caldwell, who co-authored the new study.

The researchers also observed smaller males put on feminine airs. Some would keep their brown stripes—a male trait—hidden, perhaps to lull females into a false sense of safety before setting the scene for "seduction."

(Related photo: "Six-Legged 'Hexapus' Found" [March 5, 2008].)

Adapted from an Associated Press report

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