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General Description
Appearance: Brown, reddish-orange body with white and purple markings; white suckers (personal inference).
Dimensions: Average adults can attain 23 feet in length and weigh 100 lbs. (San Francisco State University, 2008).
Anatomy: Bilateral symmetry (moves in the direction of its head) (Monaco Educational Service, 2000); mantle (at head) contains the major organs and is used for locomotion (muscular); water taken into mantle, pushed out propelling animal forward; eight arms (not called tentacles) and a supple head; very well-developed eyes (2), nervous system, brain, and sensory organs; beak at center between arms used to crush prey; tongue called a radula is used to scrape and drill for food; salivary glands near beak, contain toxins for killing prey; digestive system consists of esophagus, stomach, pancreas, liver, large intestine (cecum), and anus; nervous system consists of receptors capable of smell, touch, sight (not in color but can differentiate between different wavelengths), taste, balance, and coordination; ovaries found in females, testis found in males; ability to break off arms and regenerate them. (Wells, 1978)
Reproduction: Congregate in October; males spread their arms to show off their large suckers and appear larger (a desirable trait), they also put on a color display; larger males will eat smaller males if mistaken for a female (Scheel, 2001); sperm delivered through channel in male’s third arm, places sperm into specific opening in female’s mantle (Cerullo, 1997); after mating (November and December), female lays 20,000 to 100,000 eggs on a rock ledge; female tends eggs that she has hung from the roof of her den, not eating anything, until they hatch (about 6 to 7 months in 40oC water, temperature dependant); female dies from starvation after eggs hatch
(Cerullo, 1997; Scheel, 2001).
Embryological development: Newly hatched young rise to surface to spend 4 to 12 weeks as plankton; juveniles settle to bottom when their mantle is about 14mm in length making use of cracks and crevices referred to as “dens”(Scheel, 2001).
Sexual dimorphism: Male has enlarged suckers and ability to produce attention-getting coloration (Scheel, 2001).
Ecology: Nocturnal carnivorous hunters; prey on crabs, abalones, mollusks, fish, snails, other octopus, and scallops; food brought back to their den to consume; bites, drills or pulls apart the shells of its prey and scrapes out contents with its tongue (Scheel, 2001). Largest species of octopus in the world (National Aquarium in Baltimore, 2008).
Challenge: Octopi have many predators; adult predators include ling cod, halibut, and large marine mammals such as harbor seals, sperm whales, and sea otters; predators for juveniles are numerous and include fish and plankton eaters, (National Aquarium in Baltimore, 2008); Overcomes this challenge by night hunting (stays in its den during day) and camouflage, coloration changes to blend with its environment; its numbers are unknown but is considered a stable population but commercial fishing is a threat to its numbers (National Parks Conservation Association, 2008).
Geography: Located from the tide pool to 1,650 feet in the Pacific Ocean from Alaska to Southern California (National Parks Conservation Association, 2008).
Interesting Facts: Solitary animal; very intelligent; nicknamed “primates of the sea”; capable of memory retention even over a number of weeks; capable of problem solving (mostly getting food out of jars, etc.); curious but shy; adults recorded as putting on one pound per week up to 100 lbs.; blue copper-based blood that allows only short energy bursts; approximately a three year life span; 40 lb. grip (adults); super camouflage coloration capability by specialized cells; recorded as mischievous and sometimes affectionate in captivity (Cerullo, 1997).
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