Form and Function

Hapalochlaena lunulata are bottom dwellers that inhabit sandy shallow reefs, clumps of algae, and tide pools at depths of 0-66ft (Aquarium of the Pacific). They have adapted to their environment by staying in shallow depths because they are able to find their prey easier (Aquarium of the Pacific). They have distinct blue circle rings that cover their skin, and the center of each ring is usually a dark brown color (World Database of Marine Species). They are a deep brown to gold at rest allowing them to blend in with their surrounding environment until they are disturbed (MarineBio). Each of these rings contains chromatophores, which are pigment cells that it can expand and contract by muscular action, that causes color change when the animal is stressed (Animal Diversity Web). They flash their trademark bright iridescent blue rings that often seem to glow as a warning response to perceived danger (Blue Ringed Octopus Facts). This species of octopus has lost its ability to ink due to their ink sac becoming smaller and smaller over evolutionary time (Aquarium of the Pacific). They don’t have many predators, but if provoked they have adapted to the predators threats by having bright blue rings that signal to the predator that the octopus is poisonous or venomous, instead of the natural instinct of most octopus species to ink their predator and swim away (The Living World of Molluscs).

All Cephalopoda in general have adapted to their environment by having a soft body that can fit into any small spaces, including one as small as a pinhole (Encyclopedia of Life). They use this to hide from predators, and to search for prey in hard to reach places. They have adapted to their environment by using their muscular tentacles to search for prey (The Living World of Molluscs). Their tentacles are long allowing them to stick them into hard to reach places, and inside of their prey’s body cavity (The Living World of Molluscs). This adaptation is important to the octopus because if it lacked muscular tentacles, it would make it difficult to search and disarticulate their prey (The Living World of Molluscs). Octopus have eight arms or tentacles but they do not use them for swimming. The H. lunulata can dart quickly through the water to catch prey or to escape from predators.  Octopus swim by taking water up through their body, and pushing a jet of water out of a tube called a funnel which propels it forward (Experts123).They have this unique body shape for navigating through the water in elegant motions. The harder the octopus pushes out the water the faster it can move (Experts123).

To learn about the nutrition of this species, go to the next page.