Recognising conspecifics and behaving appropriately towards them is a crucial ability for many species. Grey seals (Halichoerus grypus) show varying capabilities in this regard: mother-pup recognition has been demonstrated in some geographical populations but is absent in others, yet there is evidence that individuals aggregate with prior associates. The recognition capabilities of newly weaned grey seal pups were investigated using class recognition trials within the habituation/dishabituation paradigm. Trials took place in pens, using pairs of individuals that either had previously cohabited (familiar) or that had never met before (stranger). Frequencies of olfactory and visual investigative behaviours (‘checks’) and aggressive interactions were recorded during trials. Familiar individuals recognised each other: paired strangers showed significantly more checks and aggressive interactions than were seen in trials pairing familiars. Oxytocin concentrations in post-trial plasma samples were analysed to investigate the underlying physiology modulating recognition abilities; however, no significant differences were detected between familiar or stranger trials. This study demonstrates that at a young age, grey seals can recognise individuals they have previously encountered. Recognition abilities in this species have adaptive value by allowing the reduction of costly aggressive interactions between familiar conspecifics, which is often cited as the first step towards the evolution of sociality in a species. This study is the first with wild subjects to find conspecific recognition abilities in a pinniped species outside of reproductive contexts. It demonstrates that even largely solitary species can be capable of recognition and pro-social behaviours that benefit them during times when they must aggregate.

中文翻译：

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在新断奶的社会可塑哺乳动物中，同种识别和攻击性降低

识别同种物种并对它们采取适当的行为是许多物种的关键能力。灰海豹（Halichoerus grypus）在这方面表现出不同的能力：在某些地理种群中已经证明了母幼识别，但在其他种群中不存在，但有证据表明个体与先前的伙伴聚集在一起。新断奶的灰海豹幼崽的识别能力在习惯化/去习惯化范式内使用类别识别试验进行了研究。试验在围栏内进行，使用以前同居（熟悉）或以前从未见过（陌生人）的成对个体。在试验期间记录嗅觉和视觉调查行为（“检查”）和攻击性相互作用的频率。熟悉的人互相认识：成对的陌生人表现出比配对熟人的试验中看到的更多的检查和积极的互动。分析了试验后血浆样品中的催产素浓度，以研究潜在的生理调节识别能力；然而，在熟悉或陌生的试验之间没有检测到显着差异。这项研究表明，在年轻的时候，灰海豹可以识别他们以前遇到过的个体。该物种的识别能力通过减少熟悉的同种物种之间代价高昂的攻击性相互作用而具有适应性价值，这通常被认为是物种社会性进化的第一步。这项研究是首次对野生受试者在生殖环境之外的鳍足类物种中发现同种识别能力。