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moved and bathed by her water jets, so they must be attached securely in order to take this treatment twenty-four hours a day for the about six months it takes for a giant Pacific octopus egg to hatch. She also manipulates the eggs with her arms, grooming them with her suckers and arm tips, which go snaking through the eggs to remove any fungus or algae growth on eggs that might choke or kill them. The egg strings are made of a chitinous, or fingernail-like, material, to hopefully be tough enough to withstand this constant manipulation.
    Because the female octopus usually doesn’t eat while she is guarding eggs, she may lose up to 50 percent of her body weight during development of the eggs. Not eating while brooding the eggs has several advantages. First,she doesn’t foul the den with food wastes or feces, which helps ensure good water quality for the eggs. She certainly could leave the den to find food or eliminate body wastes, but that would mean exposing her eggs and herself to danger from predators. Fish of several species follow foraging octopuses, hoping to snatch a bit of food, and being out eating would advertise a female’s whereabouts. Second, she won’t produce a midden of shells or other food remains in front of her maternal den. Some octopus predators (including humans) target den middens, finding them by sight or chemical cues. Third, not eating eliminates any chemicals arising from her metabolism or in her feces. Moray eels can find octopuses in their dens, but it is not known yet what chemicals from octopuses they sense. It is possible they sense some product of food metabolism that is not present while female octopuses are guarding eggs, rather than the body tissue metabolism females undergo while brooding.
    While she is tending her eggs, the female octopus survives by metabolizing muscle tissues (octopuses don’t use fat for metabolism as we do, and have very little fatty tissue), so she deteriorates considerably at the end of her life. She turns gray or pale, as though she can’t change color any more. She hardly moves. She shrinks to half her size, and actually looks old and wrinkled. She can open her den if she has blocked it up, and may manipulate the eggs somehow to stimulate them to hatch. If she is guarding small eggs, she will blow the paralarvae out of the den, usually at night, giving them a boost into open water.
    Deadly Dedication
    In Washington state’s Hood Canal, there are several sites known for their giant Pacific octopuses, with rocky outcrops having many crevices suitable for dens. Unfortunately, the waters of Hood Canal experience a period of low oxygen each fall when phytoplankton and macroalgae die, decompose, and use up oxygen in the decomposition process. Oxygen in the water during these periods has been recorded as low as 2 parts per million (ppm), compared to a normal 7 or 9 ppm. Fish and octopuses leave the deep oxygen-starved water and move into the shallows, which have more oxygen for the duration of this event. But dedicated female octopuses guarding eggs can die at the nesting sites, along with their eggs, since they won’t leave the eggs. Octopuses move back into the deep water a month or so after this occurrence, either down from the shallows or migrating from other areas.
    â€”Roland C. Anderson
    Sometimes females live after their eggs hatch and go into a state of senescence, but this behavior is more commonly seen in males. Senescent octopuses don’t hide in a den, but crawl haphazardly over the sea’s bottom, unconcerned about predators or prey. Evolution sets a fine balance between the survival of the female and the survival of the eggs; most females live until after the eggs hatch, since dying sooner would be a disaster for the potential progeny.
    The egg laying, guarding, and grooming processes have become well-shown by Olive the Octopus, a giant Pacific octopus who laid her eggs at a popular dive site in Seattle’s Puget