Amphioctopus marginatus, also known as the coconut octopus and veined octopus, is a medium-sized cephalopod belonging to the genus Amphioctopus. It is found in tropical waters of the western Pacific Ocean. It commonly preys upon shrimp, crabs, and clams, and displays unusual behaviour, including bipedal walking and gathering and using coconut shells and seashells for shelter.
Size and description
The main body of the octopus is typically around 8 centimeters (3 in) in size, and, with arms, approximately 15 centimeters (6 in) long. The octopus displays a typical color pattern with dark ramified lines similar to veins, usually with a yellow siphon. The arms are usually dark in color, with contrasting white suckers. In many color displays, a lighter trapezoidal area can be seen immediately below the eye.
Behavior and habitat
The coconut octopus is found on sandy bottoms in bays or lagoons. It frequently buries itself in the sand with only its eyes uncovered.
In March 2005, researchers at the University of California, Berkeley, published an article in Science in which A. marginatus was reported to have a bipedal behavior. It is one of only two octopus species known to display such behavior, the other species being Abdopus aculeatus. According to the article, this behavior was discovered in an area off Sulawesi, Indonesia, where the sandy bottom was littered with coconut shells. The bipedal motion appears to mimic a floating coconut.
Researchers from the Melbourne Museum in Australia claimed the creature uses tools for defense, and uses available debris to create a defensive fortress. This behavior, observed in Bali and North Sulawesi in Indonesia between 1998 and 2008, was published in the journal Current Biology in December 2009. The researchers filmed A. marginatus collecting coconut half-shells, discarded by humans, from the sea floor, carrying them up to 20 meters (66 ft), and arranging the shells to form a spherical hiding place akin to a clamshell.