Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense, Denmark.
Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761, Büsum, Germany.
Anim Cogn. 2019 Nov;22(6):947-958. doi: 10.1007/s10071-019-01286-x. Epub 2019 Jun 25.
Pinnipeds are aquatic predators feeding on a vast range of prey, and their social behaviour differs greatly between species (from extreme polygyny in some sea lions to monogamy in some true seals). It has been hypothesised that the foraging and social complexity of their lifestyle should drive the evolution of their cognitive abilities. To investigate how aware pinnipeds are of their own behaviour, a grey seal (Halichoerus grypus), two harbour seals (Phoca vitulina) and four South American sea lions (Otaria flavescens) were trained to repeat their own behaviour on command. Three already trained behaviours were used, and the animal was asked to repeat the behaviour twice to ensure that the animal recalled its own behaviour and not the command given for the previous behaviour. All three species could recall their own behaviour significantly better than by chance. The duration for which the animals could recall their behaviour was tested using a staircase paradigm. A delay was implemented between the completion of the behaviour and the command to repeat it. The delay was increased after correct responses and decreased after incorrect responses. The performance of all species fell towards chance level after 12-18 s, with no significant difference between species. These results indicate that sea lions and true seals are aware of their own behaviour and that true seals have similar short-term memory abilities. It also shows that pinnipeds have less developed short-term memory abilities compared to other aquatic predators, such as the bottlenose dolphin. The complexity of pinniped foraging and social behaviour does not seem to have driven the evolution of short-term memory abilities in these animals but might have contributed to their ability to recall their own behaviour.
鳍足类动物是水生掠食者，以广泛的猎物为食，它们的社会行为在物种间有很大的差异（从某些海狮的极端多配偶制到某些真海豹的单配制）。有人假设，它们的觅食和社会复杂性的生活方式应该推动其认知能力的进化。为了研究鳍足类动物对自己行为的意识程度，对一只灰海豹（Halichoerus grypus）、两只港海豹（Phoca vitulina）和四只南美海狮（Otaria flavescens）进行了训练，使其根据命令重复自己的行为。使用了三种已经训练过的行为，要求动物重复两次行为，以确保动物回忆起自己的行为，而不是前一次行为的命令。所有三种物种都能显著更好地回忆起自己的行为。使用阶梯范式测试了动物能够回忆起自己行为的持续时间。在完成行为和重复命令之间设置了一个延迟。如果回答正确，则增加延迟；如果回答错误，则减少延迟。所有物种的表现都在 12-18 秒后接近随机水平，物种之间没有显著差异。这些结果表明，海狮和真海豹都能意识到自己的行为，而且真海豹具有相似的短期记忆能力。这也表明，与其他水生掠食者（如宽吻海豚）相比，鳍足类动物的短期记忆能力发展程度较低。鳍足类动物觅食和社会行为的复杂性似乎并没有推动这些动物短期记忆能力的进化，但可能有助于它们回忆自己行为的能力。
