Terrestrial reproduction presents a thermoregulatory challenge for marine mammals, especially in a context of global warming. Pinnipeds, especially otariids, differ from other marine mammals in that most reproductive processes occur on land. Rocky rookeries rarely provide thermoregulatory resources (shade, pools and wet sand), so pinnipeds reduce thermal stress through thermoregulatory behaviour such as flipper exposure, flipper movement and maintenance of individual distance. Our objective was to analyse climate correlates of thermoregulatory behaviour of Southern sea lions Otaria flavescens in a colony located at the warmest end of its northern distribution on the Atlantic coast of South America. We conducted summer behavioural observations of juveniles/sub-adult (less than 150 kg) and adult (300 kg) males in the Cabo Polonio rookery, Uruguay. Solar radiation and humidity were positively correlated with thermoregulatory behaviour of sea lions, while ambient temperature had a marginal effect and wind speed had no significant effect. There were no statistically significant differences between age classes in thermoregulation activity. These and previous results on thermoregulatory behaviour of pinnipeds open the possibility that pinnipeds can be limited in abundance or distribution if climate change alters solar radiation in terrestrial rookeries during the breeding season.

中文翻译：

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生活在边缘：南美海狮Otaria flavescens在大西洋分布的北限时的温度调节行为

陆地繁殖对海洋哺乳动物提出了温度调节的挑战，特别是在全球变暖的情况下。Pinnipeds，尤其是otariids与其他海洋哺乳动物的不同之处在于，大多数繁殖过程都在陆地上进行。岩石群很少提供温度调节资源（阴影，水池和湿沙），因此针尖鸟会通过温度调节行为来降低热应力，例如鳍状肢暴露，鳍状肢运动和保持个体距离。我们的目标是分析南部海狮Otaria flavescens的温度调节行为与气候的关系在南美洲大西洋沿岸北部分布最温暖的一个殖民地。我们在乌拉圭的卡波波洛尼奥群中进行了青少年/亚成年（小于150公斤）和成年（300公斤）男性的夏季行为观察。太阳辐射和湿度与海狮的体温调节行为呈正相关，而环境温度的影响很小，风速的影响不明显。年龄类别之间的体温调节活动在统计学上没有显着差异。这些和以前有关of的温度调节行为的研究结果提出，如果气候变化在繁殖季节改变陆生鸟类群的太阳辐射，可能会限制pin的丰度或分布。