Abstract: Animals that are familiar with their environment have been reported to have greater survivorship for a number of reasons related to their knowledge of the terrain, which they recall from memory. In an initial experiment rainbowfish significantly improved their escape response towards a novel trawl apparatus over a sequence of five runs. Escape latencies were still low during a subsequent exposure 11 months after the initial exposure. While part of the improvement in escape success was certainly due to learning associated with the location of the escape route, it is likely that this was aided by habituation to the tank environment and the experimental protocol. In a follow-up experiment, fish that had been kept in the experimental tank for 3 weeks prior to testing, and had become familiar with the test tank, showed significantly lower escape latencies and escaped more often than fish that were not familiar with the test environment. It is suspected that familiarity with the testing arena decreased stress and enabled individuals to detect novel stimuli and devote more attention to them. These findings have significant implications for experimenters studying aspects of animal cognition, such as learning and memory, in laboratory situations.

Abstract: Social learning is taxonomically widespread and can provide distinct behavioural advantages, such as in finding food or avoiding predators more efficiently. Although extensively studied in bony fishes, no such empirical evidence exists for cartilaginous fishes. Our aim in this study was to experimentally investigate the social learning capabilities of juvenile lemon sharks, Negaprion brevirostris. We designed a novel food task, where sharks were required to enter a start zone and subsequently make physical contact with a target in order to receive a food reward. Naive sharks were then able to interact with and observe (a) pre-trained sharks, that is, ‘demonstrators’, or (b) sharks with no previous experience, that is, ‘sham demonstrators’. On completion, observer sharks were then isolated and tested individually in a similar task. During the exposure phase observers paired with ‘demonstrator’ sharks performed a greater number of task-related behaviours and made significantly more transitions from the start zone to the target, than observers paired with ‘sham demonstrators’. When tested in isolation, observers previously paired with ‘demonstrator’ sharks completed a greater number of trials and made contact with the target significantly more often than observers previously paired with ‘sham demonstrators’. Such experience also tended to result in faster overall task performance. These results indicate that juvenile lemon sharks, like numerous other animals, are capable of using socially derived information to learn about novel features in their environment. The results likely have important implications for behavioural processes, ecotourism and fisheries.