Abstract

ManyOtters is a multi-institutional project founded in 2023 to investigate long-term memory retention using foraging-based puzzles across captive otter species and populations. As part of this broader collaboration, Clearwater Marine Aquarium (CMA) contributed data from its three North American river otters: Opie, Boomer, and Walle. ManyOtter trials began at CMA in late November to measure long-term memory retention in these three male otters. During each trial period, the otters were exposed to 8 different foraging puzzles, ranging in complexity, for ten minutes. Two trial periods took place two months apart, and the trials were compared to look for changes in puzzle interaction time, puzzle solving time, and overall puzzle familiarity in each individual otter after not interacting with the puzzles for two months. Across otter subjects, we observed a variety of different results, widely differing by individual. Opie was overall the most consistent learner, while Boomer's pattern was mixed and Wallee frequently did not actively participate. These findings emphasize the challenges with interaction based research and the importance of exposure across a variety of otter populations. Our research will contribute to the broader ManyOtters project and act as a valuable addition to the data on long-term memory retention in otter species, particularly as it relates to skill use and puzzle solving.