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.

Library of Congress Subject Headings

North American river otter--Psychology; Long-term memory

Publication Date


Document Type


Student Type


Degree Name

Experimental Psychology (MS)

Department, Program, or Center

Psychology (CLA)


Caroline M. DeLong

Advisor/Committee Member

Jessamy Comer

Advisor/Committee Member

Tina Sutton


RIT – Main Campus

Plan Codes