The larger Pacific striped octopus is, despite its name, no bigger than a tangerine. And it has long managed to keep a low profile in the coastal waters off the eastern Pacific.

It has appeared only once in scientific journals, and only as a brief mention. In 1982, Arcadio Rodaniche, a marine biologist and illustrator, wrote about behaviors that were unheard-of among octopuses, including intimate “beak to beak” mating. His surprising findings were dismissed by other scientists.

But now, more than 30 years later, Mr. Rodaniche’s findings about the the larger Pacific striped octopus are gaining newfound credibility.

Roy Caldwell, a researcher of invertebrate studies at the University of California, Berkeley, and his team obtained 24 of these octopuses from private collectors in Nicaragua and have just published their research in the journal PLOS One.

The species is indeed unusual. While other octopuses mate by mounting, the larger Pacific striped octopus engages in “beak to beak” mating, a much closer act, as the beaks are on the underside of their bodies. Females of the species have also been found to brood over their eggs for up to six months, far longer than females of other species of octopus.

They also appear to be surprisingly social creatures. The 24 octopuses that Dr. Caldwell studied were placed in groups of eight in large tanks. None of them killed any of their tankmates (octopuses are no strangers to cannibalism), and by all appearances they seemed to get along. Male and female mates even shared a den for up to three days.

The larger Pacific striped octopus also uses a “slow bounce” to hunt. With its body flattened, and dorsal arms reaching forward, the octopus glides with sporadic bursts of hopping movements before it snatches up its prey of choice — usually shrimp. For Dr. Caldwell, the movement reminded him of a “tiger stalking a prey.” -- ASHAKI LLOYD