The coconut octopus is a master of disguise that walks on two legs

Nature · Published 3 October 2026 Swipe more like this →

In short: In the sandy depths of the tropical Pacific and Indian Oceans, the coconut octopus performs feats once thought impossible for an invertebrate. It is one of the few creatures capable of bipedal stilt-walking, and it actively collects and transports discarded debris to construct portable, spherical shelters for its own protection.

First described by malacologist Iwao Taki in 1964, Amphioctopus marginatus is a medium-sized cephalopod known for its distinct, vein-like color patterns and a pale border around its eyes. While it shares the typical anatomy of the Octopodidae family, its behavior sets it apart. The species thrives in shallow, subtidal waters along the continental shelf, often preferring muddy or sandy substrates where it can find the shells and human-made litter it uses for defense.

The most striking behavior of A. marginatus is its bipedal locomotion, or stilt-walking. Reported in a 2005 study from the University of California, Berkeley, this movement involves the octopus using two arms to walk while curling the remaining six to mimic a rolling coconut. Researchers, including Dr. Crissy Huffard, noted that this makes them unique among animals lacking a rigid skeleton. This gait is frequently employed when the octopus needs to transport stacks of debris or items that are larger than its own body.

In 2009, researchers at the Melbourne Museum documented what is considered the first evidence of true tool use in invertebrates. They observed the octopus gathering discarded coconut half-shells, carrying them up to 20 meters, and arranging them to form a protective, spherical shelter. Unlike simple opportunistic hiding, this involves the deliberate collection and preparation of materials for future use. Despite these complex behaviors, the species remains classified as Least Concern by the IUCN, though it faces ongoing pressure from fishing in its native range across the Indian and Pacific Oceans.

The life cycle of the coconut octopus is as intense as its behavior. Females lay clutches of 100,000 eggs, which are woven into long chains and deposited inside a chosen shelter. The female guards these eggs for the 15 to 17 days required for hatching, during which time she will starve to death. Once hatched, the paralarvae enter a planktonic stage, beginning a life that will eventually see them master the seafloor through their remarkable, tool-using intelligence.

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