Problem solving ability of Octopus vulgaris Lamarck (Mollusca, Cephalopoda).

Experiments presented in this study show that Octopus vulgaris Lamarck is able to open transparent glass jars closed with a plastic plug and containing a live crab (Carcinus mediterraneus). The animals remove the plus (Operandum: O) and seize the crab (Predation :P) in one single attack. The number of unsuccessful attacks appears to decrease over a series of trials (p less than .01); during the same period exploration time remains unchanged. There is a statistically significant increase in performance over trials for O (p less than .01) and P (p less than .05) mean times analyzed by single factor ANOVA, suggesting that the learning process is accomplished either by stimulus-response association or by trial and error. We propose that Octopus vulgaris is capable of learning the solutions of both problems, Operandum and Predation, thus showing a highly developed ability of "integration" of the behavioral program.