International Journal of Comparative Psychology

Making an ethogram, a repertoire of the behavior of a species or several related ones, is obviously an important foundation for any theoretical studies of their behavior. In addition, it is useful for conservation, and evolution, and as a basis for good care in captivity. But such a thorough description is neither easy nor quick. This account takes the reader on the author’s journey through lab and field work on seven species and to the struggle to publish results that make up an ethogram of octopuses in the family Octopodidae. 

The use of invertebrate models has allowed researchers to examine the mechanisms behind alcoholism and its effects with a cost-effective system. In that respect, the honey bee is an ideal model species to study the effects of ethanol (EtOH) due to the behavioral and physiological similarities of honey bees with humans when alcohol is consumed. Although both ingestion and inhalation methods are used to dose subjects in insect EtOH model systems, there is little literature on the use of the EtOH vapor-exposure method for experiments using honey bees. The experiment presented here provides baseline data for a dose EtOH-hemolymph response curve when using EtOH vapor-inhalation dosing with honey bees (Apis mellifera). Bees were exposed to EtOH vapors for 0, 1, 2.5, or 5 min, and hemolymph was collected 1 min post EtOH exposure. Hemolymph samples were analyzed using gas chromatography (GC) for hemolymph EtOH concentration. The ethanol-hemolymph level of the bees increased linearly with exposure time. The results provide a dosing guide for hemolymph EtOH level in the honey bee model ethanol-inhalation system, and thus makes the honey bee model more robust. 

Animals do not see the external world as it is. Different animals process information in different ways, even when looking at the same object. A visual illusion is a psychological phenomenon by which the eye perceives something as different from what it is. We tested whether a bottlenose dolphin produces the square-diamond illusion to see if it experiences the illusion in the same way as humans. In Experiment 1, two figures (square and diamond) of different sizes were presented in the training session and the subject had to choose the “smaller” figure. In the test session, 22 pairs of squares and diamonds of different areas were presented to see which the subject would choose. When the area difference is large, the percentage of correct responses is high, but when the area difference is small, the percentage of correct responses varies between pairs. When these results were then sorted into “small squares vs. large diamonds” and “small diamonds vs. large squares”, the percentages were significantly high in all pairs in the “small squares vs. large diamonds” group, whereas in the “small diamonds vs. large squares” group, the percentage of correct responses decreased as the difference between the areas of the two figures also decreased. In other words, this result suggests that the illusion may have come into play. Experiment 2 was a square-diamond illusion perception task. Two pairs of squares and diamonds of equal area (225 cm2 and 400 cm2, respectively) were presented and the subject’s choice was then tested. The results showed that the subject chose the square significantly more often than the diamond in both pairs. The square appeared smaller, and the diamond appeared larger to the subject, even though the fact that they had the same area (i.e., it was demonstrated that the square-diamond illusion had occurred), and this study showed that dolphins share the same visual characteristics as humans. 

The common marmoset is a nonhuman primate with a body size similar to an adult rat (approximately 250 – 450 g). This study examined the use of marmosets for behavior research on learning, focusing on the behavioral consequences of audiovisual stimuli (neither food nor liquid used as a reinforcer). A tablet (iPad®) was placed in each marmoset’s individual living cage during the experiment. On the tablet screen, nine small soundless videos of different nonhuman primate species were simultaneously presented. If the marmoset touched any of them, the touched video was zoomed-in on the screen; this was accompanied by the sound of primates chattering as the response consequence. After 2 months of repeated training sessions (10 min/day, 2 or 3 days/week), eight of the ten marmosets established the screen-touch behavior. In an extinction test for the response consequence, the screen-touch response to any of nine primate videos was examined after the presentation of a black screen instead of the above consequence. The number of touch responses decreased compared with baseline control values in three marmosets, whereas responses did not decrease in four marmosets. For the latter marmosets, it was considered that the stimulus changes from the videos to the black screen played a possible reinforcer to maintain the behavior in this test. These findings indicate that the screen-touch behavior, a new learned behavior in the nonhuman primate, could be an operant behavior with an audiovisual response consequence.