Amphioctopus marginatus
From Wikipedia, the free encyclopedia
| Amphioctopus marginatus | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Order: | Octopoda |
| Family: | Octopodidae |
| Genus: | Amphioctopus |
| Species: | A. marginatus |
| Binomial name | |
| Amphioctopus marginatus (Taki, 1964) | |
| Synonyms | |
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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 it has a number of unusual behaviors, including bipedal walking and gathering of coconut husks.
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[edit] Size and description
The main body of the octopus is typically around 8 centimeters (3 in) in size, and, with tentacles, 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 trapezoidal lighter area can be seen immediately below the eye.
[edit] 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 sticking out.
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.[1] 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.[2]
Researchers from the Melbourne Museum in Australia observed the creature's use of tools for defense, and of available debris to create a defensive fortress. The discovery of this behavior, observed in Bali and North Sulawesi in Indonesia between 1998 and 2008, was published in the journal Current Biology in December 2009.[3][4][5] The researchers filmed A. marginatus picking discarded coconut shells from the sea floor, carrying them up to 20 meters (66 ft), and arranging the shells to form a spherical hiding place.[4][6] Although octopuses often use foreign objects as shelter, the sophisticated behavior of A. marginatus when they select materials, carry and reassemble them, is far more complex.[4] The researchers define a tool as "an object carried or maintained for future use", and, according to that definition, the behavior of A. marginatus is the first documented case of tool use in invertebrates.[4][6] While the hermit crab reuses a shell which it maintains,[7] what makes A. marginatus different from the hermit crab is that A. marginatus collects shells for future use, so when the octopus is transporting the shell, it is not getting any protection from the shell, which is considered highly unusual by the researchers.[4]
