Within a species, some individuals are better able to cope with threatening environments than others. Paca (Cuniculus paca) appear resilient to over-hunting by humans, which may be related to the behavioural plasticity shown by this species. To investigate this, we submitted captive pacas to temperament tests designed to assess individual responses to short challenges and judgement bias tests (JBT) to evaluate individuals’ affective states. Results indicated across-time and context stability in closely correlated “agitated”, “fearful” and “tense” responses; this temperament dimension was labelled “restless”. Individual “restless” scores predicted responses to novelty, although not to simulated chasing and capture by humans in a separate modified defence test battery (MDTB). Restless animals were more likely to show a greater proportion of positive responses to an ambiguous cue during JBT after the MDTB. Plasticity in defensive behaviour was inferred from changes in behavioural responses and apparently rapid adaptation to challenge in the different phases of the MDTB. The results indicate that both temperament and behavioural plasticity may play a role in influencing paca responses to risky situations. Therefore, our study highlights the importance of understanding the role of individual temperament traits and behavioural plasticity in order to better interpret the animals’ conservation status and vulnerabilities.

中文翻译：

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Paca防御行为的气质，可塑性和情绪（哺乳动物，Hystricognatha）

在一个物种中，有些人比其他人更有能力应对威胁环境。帕卡（Cuniculus paca）表现出对人类过度狩猎的适应力，这可能与该物种表现出的行为可塑性有关。为了对此进行调查，我们将诱捕的帕卡斯语用于气质测试，旨在评估个人对短期挑战的反应，并使用判断偏差测试（JBT）来评估个人的情感状态。结果表明，在密切相关的“激动”，“恐惧”和“紧张”反应中，跨时间和上下文稳定。这种气质维度被标记为“不安”。个别的“不安定”分数可预测对新颖性的反应，尽管不是对人类在单独的改良防御测试电池（MDTB）中模拟的追逐和捕获做出的反应。在MDTB之后的JBT期间，躁动不安的动物更有可能对歧义线索表现出更大比例的阳性反应。防御行为的可塑性是由行为反应的变化以及显然在MDTB的不同阶段快速适应挑战所推断的。结果表明，气质和行为可塑性都可能在影响对风险情况的反应中发挥作用。因此，我们的研究强调了理解个体气质特征和行为可塑性的作用的重要性，以便更好地解释动物的保护状况和脆弱性。