Coconut Octopus

Amphioctopus marginatus, also referred to as the coconut octopus or veined octopus, is a medium-sized cephalopod belonging to the genus Amphioctopus within the family Octopodidae. It inhabits the tropical waters of the western 🌊 Pacific Ocean and exhibits a variety of intriguing behaviors, including unique locomotion and tool usage. This species primarily preys on shrimp, crabs, and clams.

Originally described in 1964 by 🇯🇵 Japanese malacologist Iwao Taki as Octopus marginatus, this species was also classified under the synonym Amphioctopus marginatus. In 1976, Z. Dong proposed the name Octopus striolatus; however, this classification was not accepted as valid within the scientific community.

The coconut octopus typically has a body length of approximately 8 centimeters (3 inches) and, including its arms, reaches a length of around 15 centimeters (6 inches). Its distinct coloration features dark, vein-like lines and a yellow siphon, with dark arms contrasting with white suckers. Notably, a lighter trapezoidal area is commonly observable below the eye during various color displays.

Predominantly feeding on Calappa crabs and bivalves, Amphioctopus marginatus lays eggs in clutches of 100,000, each measuring about 3 millimeters (0.12 inches) long.

In March 2005, researchers from the University of California, Berkeley, published findings in Science that documented A. marginatus exhibiting bipedal locomotion, or "stilt-walking." This involves rolling two arms while using the remaining ones to mimic a floating coconut, a behavior first observed off Sulawesi, 🇮🇩 Indonesia, where coconut shell debris is prevalent. This species, alongside Abdopus aculeatus, is among the few known to display such locomotion.

Further observations in 2009 by researchers from Melbourne Museum, 🇦🇺 Australia, revealed the coconut octopus's capacity for tool use. Utilizing available materials such as coconut shells, the octopus constructs shelters for concealment and defense. The octopus was seen collecting discarded coconut halves from the seafloor, transporting them up to 20 meters (66 feet), and arranging them into a protective sphere, indicative of sophisticated tool use in invertebrates. While other octopus species have been noted for using shells for concealment, Amphioctopus marginatus demonstrates the first recorded instance of deliberately preparing and storing tools for future use—a behavior termed "true tool use" by the Melbourne Museum. In performing such tasks, the octopus often employs bipedal motion to transport items larger than itself.

Amphioctopus marginatus is broadly distributed across neritic, tropical waters in regions including the 🌊 Indian Ocean, 🌊 Red Sea, Northwest and Western 🌊 Pacific Ocean, and Southeast Asian Sea. Classified as Least Concern on the IUCN Red List, the species displays resilience against human impacts due to its extensive distribution, despite potential threats from fishing activities.

Preferring shallow, subtidal zones along the continental shelf, this species occupies environments with mud and sand substrates and can thrive at depths reaching up to 190 meters (620 feet).