Creature of the Month: Day Octopus
By: Alexandrya Robinson

Looking out on the reef, oftentimes you will see a whole host of colorful species that call the reef home. However, in order to see one of these interesting organisms, you have to look a bit closer. Octopus cyanea, better known as the day octopus or he‘e in Hawai‘i, has the ability to change colors with specialized chromatophore cells that, when squeezed or relaxed, change color. This makes the day octopus highly adept at camouflage. Additionally, the fact that these cephalopods can easily maneuver into very small and tight spaces allows them to hide and escape predators including sharks, dolphins, large fishes, eels, and Hawaiian monk seals.

For divers seeking out these cool creatures, looking for little caves with broken shells littering the sand outside, often called octopus gardens, can help. The shells belong to bivalves, shrimps, and crabs, the main prey of the octopus. Since the main active feeding hours of this species are during the day, there is a good chance for divers and snorkelers to catch sight of feeding octopods. A rarer sight, only occurring during certain times of the year, is the female day octopus tending to her eggs instead of hunting.

The mating process of this octopus is unique. When females are approached by a male, a specialized arm filled with spermatophores is inserted into her mantle cavity, which contains her oviducts. Here, the eggs are fertilized, and the female octopus goes to her den where she lays her brood. During this time, the mother moves oxygenated water over the eggs constantly while they incubate. That means she never leaves their side, even to eat, which ultimately results in her starving. However, her hard work pays off when a whole new generation of octopods are hatched. In this planktonic stage, the juvenile octopods feed on other small animals within the water column. Keep an eye out for these incredible cephalopods on the reef!