Data from: Mitogenomes and relatedness do not predict frequency of tool use by sea otters

Many ecological aspects of tool-use in sea otters are similar to those in Indo-Pacific bottlenose dolphins. Within an area, most tool-using dolphins share a single mitochondrial haplotype and are more related to each other than to the population as a whole. We asked whether sea otters in California showed similar genetic patterns by sequencing mitogenomes of 43 otters and genotyping 154 otters at 38 microsatellite loci. There were six variable sites in the mitogenome that yielded three haplotypes, one found in only a single individual. The other two haplotypes contained similar percentages (33 and 36%) of frequent tool-users and a variety of diet types. Microsatellite analyses showed that snail specialists, the diet specialist group that most frequently used tools, were no more related to each other than to the population as a whole. The lack of genetic association among tool-using sea otters compared to dolphins may result from the length of time each species has been using tools. Tool-use in dolphins appears to be a relatively recent innovation (<200 years) but sea otters have likely been using tools for many thousands or even millions of years.海獭使用工具的诸多生态学特征与印度-太平洋宽吻海豚高度相似。在某一区域内，多数使用工具的海豚共享同一种线粒体单倍型（mitochondrial haplotype），且彼此间的亲缘关系较之与种群整体的亲缘关系更为紧密。本研究针对加利福尼亚州海獭是否存在类似遗传模式展开探究，对43只海獭的线粒体基因组（mitogenome）进行测序，并对154只海獭的38个微卫星位点（microsatellite loci）开展基因分型分析。该线粒体基因组中共存在6个可变位点，可划分出3种单倍型；其中仅有一种单倍型仅在单一个体中被检测到。剩余两种单倍型中，频繁使用工具的个体占比相近（分别为33%与36%），且涵盖了多样的觅食类型。微卫星分析结果显示，蜗牛特化觅食类群——这是最频繁使用工具的觅食特化类群——彼此间的亲缘关系并未较其与种群整体的亲缘关系更为紧密。相较于海豚，使用工具的海獭之间未呈现显著的遗传关联，这一现象或源于两个物种使用工具的时长差异。海豚的工具使用行为相对较新（距今不足200年），而海獭使用工具的历史则可能长达数千年甚至数百万年。