An ongoing study led by two San Francisco Bay Area scientists, Dr Roy Caldwell of the University of California, Berkeley, and Dr Richard Ross of the California Academy of Sciences’ Steinhart Aquarium, sheds some light on long-ignored octopus species – the Larger Pacific Striped Octopus.
Larger Pacific Striped Octopus displaying stripes and spots (Richard Ross)
“The Larger Pacific Striped Octopus is the most beautiful octopus I have ever seen,” Dr Caldwell said.
The Larger Pacific Striped Octopus displays striking color and shape changes, shifting in an instant from a nondescript dark reddish black ‘leaf,’ to an awesome clash of white and black stripes over constellations of white spots.
Besides coloration, what makes this species so different from other octopuses is the way it seems to ignore what has become the standard story of octopus social structures, mating and motherhood.
Instead of living a solitary life, and coming together briefly for mating like almost all other octopuses, the Larger Pacific Striped Octopus can cohabitate in pairs, sometimes sharing the same den. Groups are reported to live in associations of 40 or more animals.
Left: Larger Pacific Octopuses mate dangerously ‘beak to beak’ (Richard Ross) Right: Larger Pacific Striped Octopus presenting a dark ‘leaf’ display (Roy Caldwell)
Instead of mating from a safe distance like most other octopuses, or males mounting females as occurs in a few others, the Larger Pacific Striped Octopus are the only octopuses known to mate ‘beak to beak’ with their ventral, suckered sides touching – a position that may be viewed as dangerous considering the cannibalistic nature of cephalopods.
Most female octopuses mate and brood a single clutch of eggs through hatching, only to die as their offspring swim into the great unknown. The Larger Pacific Striped Octopus breaks this tragic tradition.
The female Larger Pacific Striped Octopus is iteroparous meaning that she lays and broods many clutches of eggs over her lifetime. One of the only other octopuses known to share this trait is the Lesser Pacific Striped Octopus (Octopus chierchiae), a tiny close relative to the Larger Pacific Striped Octopus.
Until the scientists began studying the Larger Pacific Striped Octopus, the creature was virtually ignored.
In 1991, Dr Arcadio Rodaniche published a short abstract, providing a tantalizing glimpse of this intriguing animal based on observations he made at the Smithsonian Tropical Research Institute in Panama in the late 70’s. Unfortunately, detailed information contained in a full manuscript documenting the Larger Pacific Striped Octopus’ unique social and reproductive behavior was never published.
“Rodaniche’s descriptions of the behavior of this species were so outside the norm of what biologists at the time thought octopuses did, they were dismissed by other cephalopod biologists,” Dr Caldwell explained.
Unable to pass peer review, the manuscript was never published and the animal was forgotten. Living Larger Pacific Striped Octopuses weren’t seen again until they were rediscovered in 2012.
“We are thrilled to confirm many of Rodaniche’s observations,” added Dr Ross.
Dr Caldwell, Dr Ross and colleagues are currently working on a species description and are hoping to mount an expedition to document the behavior of this octopus in its natural habitat.
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Bibliographic information: A. F. Rodaniche. 1991. Notes on the Behavior of the Larger Pacific Striped Octopus, An Undescribed Species of the Genus Octopus. Bulletin of Marine Science, vol. 49, no. 1-2, pp. 667
