Institute of Information Problems, Russian Academy of Science, Bol`shoi Karetni per. 19, Moscow 101447, Russia

Abstract

In the behavioural experiments when showing simultaneously coloured stimuli (food targets) and also in choosing between two stimuli, red and blue, it had been shown with a high level of reliability that the hungry Bufo viridis which had not been fed for at least a week, in the overwhelming majority of cases chose the red-coloured food targets. Within 1-3 days after an abundant feeding, in the same animals the changes occurred in their preferences of the prey colour. The percentage of choosing the blue targets by the satiated toads significantly increases. In a separate series of experiments had been demonstrated that the changing motivation is conditioned by colour, since hungry and satiated Bufo viridis under conditions of simultaneous demonstration of four stimuli, black and three different grey stimuli, chose exclusively the black stimulus.