It turns out most donвЂ™t live up to their вЂdenizen of the deepвЂ™ reputation,вЂќ says former UC Berkeley doctoral student Christine Huffard of the Monterey Bay Aquarium Research Institute. вЂњEach time a different type of octopus is studied, we need to redefine our theories about their behavior. вЂњIt reminds us how much we still have to learn about the mysterious world of cephalopods.вЂќ вЂњPersonally observing and recording the incredibly unique cohabitation, hunting, and mating behaviors of this fascinating octopus was beyond exciting-almost like watching cryptozoology turn into real-life zoology,вЂќ Ross says. Ross even put some on display at the academyвЂ™s Steinhart Aquarium, where guests could have observed several pairs mating daily and producing multiple clutches of eggs. вЂDenizens of the deepвЂ™ДЇor a new study, published in the journal PLOS ONE, Caldwell and coauthor Richard Ross of the California Academy of Sciences obtained 24 live specimens from a pet supplier between 20 and observed them in their laboratories. Females grow to less than 7 centimeters across (3 inches), while males max out at less than 4.5 centimeters (2 inches). The animal lives in water between 40 and 50 meters (150 feet) deep, typically on muddy, sandy plains at the mouths of rivers, probably living in cast-off shells or rock cavities. Both are вЂњharlequinвЂќ octopuses, so called because of their semi-permanent stripes and spots. The species has still not been officially described and has no scientific name.Д¬aldwell, too, once doubted the brief description of the octopusвЂ™s behavior, and only stumbled across the species while pursuing a smaller relative, Octopus chierchiae, on the Pacific coast of Central America.

The behavior was so at odds with accepted octopus behavior, however, that he was unable to publish more than an abstract.

Panamanian biologist Arcadio Rodaniche first observed much of this strange behavior in the 1970s while studying captured specimens in a saltwater swimming pool in Panama. вЂњThere are a lot of species of octopus, and most have never even been seen alive in the wild and certainly havenвЂ™t been studied.вЂќ While their behavior and neurobiology have been extensively studied, most research is based on observations of just a handful of the more than 300 species of octopus worldwide, Caldwell says. The peculiar behaviors seen in the larger Pacific striped octopus are actually a testament to how little is known about most octopuses. The females mate frequently and lay eggs over several months, whereas the females of most known octopuses die after a single brood. The pair grasp each otherвЂ™s arms sucker-to-sucker and mate beak-to-beak, as if kissing. Mating pairs have even been observed to share meals in an unusual beak-to-beak position. The white object is a packet of the maleвЂ™s sperm being passed down the hectocotylus to be deposited into the femaleвЂ™s mantle cavity. Just under the femaleвЂ™s eye and to the left of her funnel, the maleвЂ™s mating arm (hectocotylus) enters her mantle cavity. A mating pair of larger Pacific striped octopus the male is the darker of the two.

While most species are solitary, these have been seen in groups of up to 40 off the Pacific coasts of Nicaragua and Panama.ДЄnd while male octopuses typically share sperm with females at armвЂ™s length, ready to flee should the female get aggressive or hungry, mating pairs of this octopus when observed in captivity sometimes cohabit in the same cavity for at least a few days while mating, with little indication of escalated aggression. The creature, known as the larger Pacific striped octopus, also turns out to be among the most gregarious of known octopuses. вЂњWhen this octopus sees a shrimp at a distance, it compresses itself and creeps up, extends an arm up and over the shrimp, touches it on the far side, and either catches it or scares it into its other arms.вЂќ Beak-to-beak mating

вЂњOctopuses typically pounce on their prey or poke around in holes until they find something. вЂњIвЂ™ve never seen anything like it,вЂќ says Roy Caldwell, professor of integrative biology at the University of California, Berkeley. Unlike most octopuses, which tackle their prey with all eight arms, a rediscovered tropical octopus subtly taps its prey on the shoulder and startles it into its arms. University University of California, Berkeley

Octopus beak