An Investigation of Novel Object Recognition Memory in a North American River Otter (Lontra canadensis)

Memory is the mental processes of receiving and storing information for later retrieval, with long-term memories being those that are stored longer than 30 seconds. Little research has been done to investigate memory in any of the 13 species of otters. Object recognition memory has the potential to aid otters in identifying conspecifics, prey, and predators, which would contribute to better survival and fitness. Object recognition memory has been investigated in many non-human animals using the novel object recognition (NOR) task. This study was the first to investigate long-term object recognition memory in the North American river otter using the NOR task. The subject was one adult male otter, Sailor, that resided at the Seneca Park Zoo in Rochester, NY. The stimulus pairs for this task were multimodal (3D objects and odorants) to take advantage of multisensory facilitation. The current study investigated three memory intervals: 10 minutes, 1 hour, and 24 hours (each interval included 10 sessions). There were two dependent variables: time spent with each stimulus pair and number of explorations (the otter making physical contact with, or being within a few centimeters of the stimulus pair). The results did not provide evidence for memory at any of the memory intervals. This may have been due to the otter spending significantly more time on the left side of the enclosure because of the experimental setup. Other limitations included the single-subject design and lack of information about what is discriminable in both vision and olfaction in otters. Future research should further investigate long-term memory in otters using either the NOR task or a puzzle feeder task, as well as with additional otter subjects. There is still much to be learned about memory in otters, which could have applications for animal welfare in zoos and can inform conservation efforts for otters

Visual perception of photographs of rotated 3D objects in goldfish (Carassius auratus)

© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Wegman, J. J., Morrison, E., Wilcox, K. T., & DeLong, C. M. Visual perception of photographs of rotated 3D objects in goldfish (Carassius auratus). Animals, 12(14), (2022): 1797, https://doi.org/10.3390/ani12141797.This study examined goldfishes’ ability to recognize photographs of rotated 3D objects. Six goldfish were presented with color photographs of a plastic model turtle and frog at 0° in a two-alternative forced-choice task. Fish were tested with stimuli at 0°, 90°, 180°, and 270° rotated in the picture plane and two depth planes. All six fish performed significantly above chance at all orientations in the three rotation planes tested. There was no significant difference in performance as a function of aspect angle, which supported viewpoint independence. However, fish were significantly faster at 180° than at +/−90°, so there is also evidence for viewpoint-dependent representations. These fish subjects performed worse overall in the current study with 2D color photographs (M = 88.0%) than they did in our previous study with 3D versions of the same turtle and frog stimuli (M = 92.6%), although they performed significantly better than goldfish in our two past studies presented with black and white 2D stimuli (M = 67.6% and 69.0%). The fish may have relied on color as a salient cue. This study was a first attempt at examining picture-object recognition in fish. More work is needed to determine the conditions under which fish succeed at object constancy tasks, as well as whether they are capable of perceiving photographs as representations of real-world objectsThis work was supported with a RIT College of Liberal Arts Faculty Development Grant to CMD and the RIT Paul A. and Francena L. Miller Research Fellowship awarded to CMD from the Rochester Institute of Technology

Investigating Object Recognition Memory Using Sensory Enrichment with a North American River Otter (<i>Lontra canadensis</i>)

Research studies that shed light on cognitive and perceptual abilities in otters can utilize tasks that provide environmental, structural, food-based, sensory, or cognitive enrichment. The current study examined the use of the novel object recognition task, a task commonly used to study memory in non-human animals, as a form of sensory enrichment. The subject of the current study was an adult male otter that resided at the Seneca Park Zoo in Rochester, NY, USA. The stimulus pairs for this task were multisensory (3D objects and odorants). In this study, three memory intervals were investigated: 10 min, 1 h, and 24 h (each memory interval included 10 sessions). The otter spent only 15% of his time near the stimulus pairs and engaged in very few explorations, suggesting that this was not an effective form of sensory enrichment and did not provide any evidence for long-term memory. These results contrast strongly with our previous studies with otters using a two-alternative forced-choice task that provided engaging cognitive enrichment. We suggest that cognitive enrichment, including enrichment via training (and food-based enrichment), may be more effective for otters than sensory enrichment. Future research should further investigate cognitive phenomena in otters using tasks involving cognitive enrichment. These types of studies can improve enrichment practices and promote positive welfare for otters in zoos, inform conservation efforts, and grow our limited knowledge of otter perception and cognition