The Neotropical otter, Lontra longicaudis, is a semiaquatic mustelid that preys upon fish, amphibians, and crustaceans, in variable proportions according to habitat and/or season. Due to the difficulty of observing this species in the wild, information on its ecology is typically obtained through vestiges, such as feces, which usually do not provide data at the individual level. Thus, this study aimed to assess temporal and individual variation in the diet of the Neotropical otter through chronologically ordered carbon (δ13C) and nitrogen (δ15N) stable isotopes data, as a proxy for dietary variation. For this purpose, isotopic values of 127 fragments of vibrissae collected from 21 individuals found dead along three coastal regions of southern Brazil were analyzed. Values ranged between − 24.0 and − 12.9‰ for δ13C and from 10.6 to 18.4‰ for δ15N. Vibrissae isotopic longitudinal data were variable, indicating individual changes in the proportion of food items consumed and in foraging sites that spanned from freshwater to marine environments. Most of the populational variation in isotopic composition resulted from differences between individuals. The results of this study revealed temporal and individual variation in resource and habitat use by the Neotropical otter in three coastal ecosystems, and suggest that a high individual foraging specialization may occur in this species.

中文翻译：

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触须科稳定同位素分析揭示的新热带水獭 Lontra longicaudis (Olfers, 1818) (Carnivora, Mustelidae) 饮食的时间和个体差异

新热带水獭，Lontra longicaudis，是一种半水生的鼬科动物，根据栖息地和/或季节以不同的比例捕食鱼类、两栖动物和甲壳类动物。由于难以在野外观察该物种，其生态信息通常是通过粪便等遗迹获得的，通常不提供个体层面的数据。因此，本研究旨在通过按时间顺序排列的碳 (δ13C) 和氮 (δ15N) 稳定同位素数据评估新热带水獭饮食的时间和个体变化，作为饮食变化的代表。为此，分析了从巴西南部三个沿海地区发现的 21 个死亡个体中收集的 127 个触须碎片的同位素值。δ13​​C 的值介于 - 24.0 和 - 12.9‰ 之间，δ15N 的值介于 10.6 到 18.4‰ 之间。触须的同位素纵向数据是可变的，表明消费的食物比例和从淡水到海洋环境的觅食地点的个体变化。同位素组成的大部分种群变异是由个体之间的差异引起的。这项研究的结果揭示了新热带水獭在三个沿海生态系统中资源和栖息地利用的时间和个体差异，并表明该物种可能存在高度的个体觅食专业化。