|
Note: The links for video 1 and 2 pointed to the wrong
movies on Monday 21 March. As of Tuesday morning, the links,
captions and credits are all accurate.
Two octopus species can walk on just two arms, and they appear
to use the other six arms to disguise themselves -- either
as rolling coconuts or clumps of floating algae, according
to a new "Brevia" article in the 25 March 2005 issue
of the journal Science. Before Christine Huffard
and colleagues had observed of this fancy octopus footwork,
walking on two limbs was thought to be restricted to creatures
with muscles attached to bones or other skeletal structures.
Instead of muscles and bones, the small octopuses from Australia
and Indonesia rely on flexible muscles supported by the fluid
inside them. Using underwater video footage, the authors analyzed
the arm movements of the "coconut octopus," Octopus
marginatus, whose body is roughly the size of a small
apple, and the "algae octopus," Octopus aculeatus,
a species with walnut-sized bodies. The regular motions of
the arms and the amount of time each arm spends in contact
with the sandy ocean floor qualify both of these creatures
as official two-limbed walkers that perform "bipedal
locomotion," the authors say. The tiptoeing is different
enough from the traditional octopus crawl that it may allow
octopuses move without alerting predators of their presence.
Science is published by AAAS, the non-profit science
society.
Looking for images or video? View past Science
multimedia at the Science
Multimedia Gallery.
|
 |
| VIDEO
is available. |
|
 |
|
O. aculeatus uses its arms to catch its prey,
as well as
move along the bottom. This one is eating a mantis shrimp.
[Image courtesy of Roy Caldwell of UC Berkeley]
|
| |
|
 |
|
O.aculeatus sitting in an aquarium with its
long arms
curled behind its body and its suckers visible. The
animal rolls along the suckers when it walks.
[Image courtesy of Roy Caldwell of UC Berkeley]
|
| |
|
 |
|
Fleshy projections on the skin of O. aculeatus
allow
it to camouflage like algae in its natural habitat.
[Image courtesy of Roy Caldwell of UC Berkeley]
|
| |
|
 |
|
Fleshy projections on the skin of O. aculeatus
allow it to
camouflage like algae in its natural habitat.
[Image courtesy of Roy Caldwell of UC Berkeley]
|
| |
|
 |
|
O.aculeatus on rock with algae. You can see
the branched projections (papillae) sticking up from
its skin. These are fleshy projections raised and relaxed
by muscles in the skin.
[Image courtesy of Roy Caldwell of UC Berkeley]
|
Video:
Download video1
of Octopus aculeatus or "algae octopus"
walking. Animal is walking backward on the ventral
pair of arms using a rolling gait. Note all other
arms are raised above the head for camouflage as a
floating clump of algae.
[Video 1 courtesy of Christine Huffard]
Download video
2 of Octopus marginatus or "coconut octopus"
walking. Animal is walking backward while six arms
are held under the rounded body as if it were a coconut
shell rolling along the ocean floor.
[Video 2 courtesy of Sea Studios Foundation ©]
|
|
