384: Stealthy Bipedal Octopuses -- Miller 2005 (324)

Stealthy Bipedal Octopuses -- Miller 2005 (324): 3 -- sciencenow:

That's why the behavior of [Octopus] aculeatus is so fascinating, says Christine Huffard, a graduate student at the University of California, Berkeley, who led the new study. The octopus can scurry along the seafloor on the tips of two arms--planting one "foot" before the other in a motion surprisingly reminiscent of human walking--while it keeps its other six arms extended in a fairly convincing algae imitation (see links below).

In the 25 March issue of Science, Huffard and colleagues also report that an Indonesian octopus, O. marginatus, performs a similar trick, walking on two arms with its other arms balled up beneath its body. The researchers interpret this behavior, perhaps somewhat imaginatively, as an impression of a rolling coconut. Both octopuses can move slightly faster in stealth mode than they can when crawling with several arms, another possible advantage, Huffard says.

Videos at Thoughts from Kansas. Camouflage is classic natural selection at work. These are co-evolved with aspects of their environment.