Two-Spotted Octopus (Octopus bimaculoides)
Contributed by TPERP Randal Rand
Range: O. bimaculoides from San Simeon and Channel Islands to Ensendada. O. bimaculatus from Santa Barbara and the Channel Islands to the southern tip of Baja California.
Environment: O. bimaculoides use protected holes and crevices in pools, middle and low intertidal zones, also on mud flats; older animals often subtidal to depths of 20 meters on rocks or in kelp beds. O. bimaculatus are usually farther off shore from the lowest intertidal to a depth of 50 meters.
Diet: Adults feed on molluscs, crustaceans, and occasionally fishes. Toxic secretions of the posterior salivary glands are used to paralyze the prey. In the case of shelled molluscs the poison is injected through a small hole rasped in the shell by the radula
Life cycle: After hatching the young remain on the bottom
Life span: About a year; death usually occurs some time after mating for males; females usually die after their broods have hatched.
Reproduction: Males deposit a sperm packet into the females with one of their specialized tentacles. The deposit is done either in a mounted position or from a distance with his outstretched tentacle. Females will tend to their eggs for a period of two to four months.
Behavior: Typically shy by nature, but their intelligence also makes them very curious and they will often interact with humans. If distressed they will attempt to flee and may often dispense a cloud of ink to distract their pursuers.
Other facts: Their camouflage gives them the ability to instantly adapt to their surroundings, matching both texture and color even though they only see in black and white.
The two species are so similar in most respects that for more then 60 years the two-spotted octopus was thought to represent a single species.
Caution: Picking up or handling live octopuses often removes their protective mucus coating, exposing the animals to bacterial infections.
Scientific name: Octopus bimaculoides & Octopus bimaculatus
Common name(s): two-spotted octopus, mud-flat octopus
Intertidal invertebrates of California. Robert H. Morris, Donald P. Abbott and Eugene C. Haderlie, eds. Stanford, CA:Stanford University Press 434-436
Encylopedia of Tidepools & Rocky Shores, Edited by Mark W. Denny and Steven D. Gaines
Last revised 29-Jul-13