Signal Use by Octopuses in Agonistic Interactions

Signal Use by Octopuses in Agonistic Interactions

Cephalopods show behavioral parallels to birds and mammals despite considerable evolutionary distance [1, 2]. Many cephalopods produce complex body patterns and visual signals, documented especially in cuttlefish and squid, where they are used both in camouflage and a range of interspecific interactions [1, 3-5]. Octopuses, in contrast, are usually seen as solitary and asocial [6, 7]; their bod...

Octopuses

What are they? Octopuses and their relatives, the cuttlefish and squids, form the class of modern cephalopods (coleoids). These are soft-bodied molluscan invertebrates like garden snails or sea hares (Aplysia). The modern cephalopods appeared in the sea at the same time as bony fish; more than 200 million years ago. The old cephalopods are virtually extinct — their only living representative is...

Single-session learning by octopuses.

Underwater bipedal locomotion by octopuses in disguise.

Here we report bipedal movement with a hydrostatic skeleton. Two species of octopus walk on two alternating arms using a rolling gait and appear to use the remaining six arms for camouflage. Octopus marginatus resembles a coconut, and Octopus (Abdopus) aculeatus, a clump of floating algae. Using underwater video, we analyzed the kinematics of their strides. Each arm was on the sand for more tha...

Visual Discrimination of Distance by Octopuses

If two stimuli are presented to an octopus simultaneously, but at different distances from the animal, the nearer of the two is usually attacked. This preference was used to test the ability of octopuses to discriminate distance. White discs, 37 mm in diameter, were used as stimuli, and two parameters were varied: the distance of the farther stimulus from the animal (D), and the difference betw...