Between-individual variation in behavior can emerge through complex interactions between state-related mechanisms, which include internal physiological constraints or feedback derived from the external environment. State-related conditions can be especially influential during early life, when parental effort and exposure to social stress may canalize consistent differences in offspring hormonal profiles and foster specific behavioral strategies. Here, we unravel how relevant state variables, including sex, somatic condition, local population density, and maternal traits, contribute to within-cohort differences in stress, sex, and thyroid hormone axes in dependent Galapagos sea lions with the primary goal of understanding downstream effects on boldness, docility, habitat use, and activity. Pups within denser natal sites had higher levels of cortisol and thyroid T4, a prohormone and proxy for metabolic reserves, likely as an adaptive physiological response after exposure to increased numbers of conspecific interactions. Furthermore, considering maternal effects, mothers in better body condition produced pups with higher testosterone yet downregulated basal cortisol and thyroid T4. This hormonal profile was correlated with increased boldness toward novel objects and attenuated stress responsiveness during capture. Intriguingly, pups with increased thyroid T3, the biologically active form, maintained faster somatic growth and were observed to have increased activity and extensively explored surrounding habitats. Collectively, these findings provide comprehensive evidence for several links to hormone-mediated behavioral strategies, highlighted by variation in socio-environmental and maternally derived input during a foundational life stage.

行为之间的个体差异可以通过与状态相关的机制之间的复杂相互作用而出现，这些相互作用包括内部生理约束或来自外部环境的反馈。当父母的努力和暴露于社会压力下时，与国家相关的条件可能会特别有影响力，父母的努力和暴露于社会压力下可能会抵消后代荷尔蒙特征的持续差异，并养成特定的行为策略。在这里，我们将阐明相关的状态变量（包括性别，躯体状况，局部人口密度和母性）如何对依赖的加拉帕戈斯海狮的同龄人在压力，性别和甲状腺激素轴方面的差异做出贡献，其主要目标是了解下游对勇气，温顺，栖息地使用和活动的影响。出生地点较密的幼仔体内的皮质醇和甲状腺T4含量较高，是激素和代谢储备的代表，很可能是暴露于同种相互作用次数增加后的适应性生理反应。此外，考虑到母体的影响，身体状况较好的母亲所生的幼仔睾丸激素水平较高，而基底皮质醇和甲状腺T4却下调。这种荷尔蒙的轮廓与对新颖物体的更大胆量和在捕获过程中减弱的应激反应性相关。有趣的是，具有生物活性形式的甲状腺T3含量增加的幼犬，保持了较快的体细胞生长，并观察到其活动性增强，并广泛探索了周围的栖息地。总的来说，这些发现为激素介导的行为策略的若干联系提供了全面的证据，