Recognition of a 3D snake model and its 2D photographic image by captive black tufted-ear marmosets (Callithrix penicillata).
Two-dimensional (2D) displays of real three-dimensional (3D) objects are frequently used experimental tools in animal studies. Whether marmoset monkeys, with their highly diverse and complex anti-predation strategies, readily recognized 2D representations of potential threats has yet to be determined, as seen in other primates. Thus, the behavioral responses of adult captive black tufted-ear marmosets (Callithrix penicillata) toward an unfamiliar motionless snake-model and its photograph were assessed. Pictorially naïve subjects were randomly divided into two groups (n = 12/each) and submitted to two trials. Group 1 was initially exposed to the 3D object and after 1 week to its photograph. Group 2 was first presented the picture and only tested with the real object 1 week later. All 15-min trials were divided into three consecutive 5-min intervals: pre-exposure, exposure and post-exposure. In the presence of the 3D snake object, regardless of its presentation order, the frequency of direct gazes, head-cocks, tsik-tsik alarm/mobbing calls and genital displays increased significantly. The photograph induced a similar response, although only when the object had been previously presented, as significantly higher levels of these behaviors were seen in Group 1 than Group 2. Proximity to the stimulus, aerial scan, terrestrial glance, displacement activities and locomotion were not consistently influenced by the stimuli's presence and/or order of presentation. Therefore, marmosets recognized and responded appropriately to biologically and emotionally relevant 3D and 2D stimuli. Since the aversive/fearful reactions toward the photograph were only seen after the snake object had been presented, the former seems to be essentially a learned response.
Emile
Nally
N
Department of Pharmaceutical Sciences, School of Health Sciences, University of Brasilia, Brasilia, DF, CEP 70910-900, Brazil.
Barros
Marilia
M
D000818:Animals; D001522:Behavior, Animal; D002144:Callithrix / Q000523:psychology*; D004644:Emotions; D005239:Fear; D005260:Female; D008297:Male; D008954:Models, Biological; D010781:Photography; D021641:Recognition, Psychology; D012911:Snakes; D014796:Visual Perception