Octopus are cephalopod mollusks that have eight arms equipped with two rows of suckers. There are more than 100 species of octopi living in marine waters throughout the world. The best known species is the common octopus, which lives in tropical seas.
An octopus mother lays between 20,000 and 100,000 eggs inside a rocky cavern over the course of several days. She nurtures the eggs for a period of 150 days to seven months or more, depending on water temperatures.
Once the octopus eggs hatch, they are in the larvae stage. At this point the hatchlings swiftly make their way to the water's surface.
As juveniles, octopi are considered plankton. During this stage, they feed on other plankton that live near the ocean's surface.
Most octopus species live for only 12-18 months and breed only once during their lifetime, according to the Wild Fisheries Research Program, New South Wales Department of Primary Industries.
Just before death, octopi enter the senescence stage of its life cycle, during which period it will eat little, according to "Octopus Senescence: The Beginning of the End" by Roland C. Anderson, Ph.D, and James B. Wood, Ph.D.