A solitary rough-toothed dolphin (Steno bredanensis) in a superport area on northern Rio de Janeiro State, SE Brazil

Abstract: The solitary behavior is an unusual and peculiar behavior reported in a few sociable dolphin species. This study presents the solitary behavior of an adult rough-toothed dolphin, Steno bredanensis, in the Açu Superport (21º49’S; 041º00’W), northern Rio de Janeiro State, SE Brazil. Data about the dolphin were obtained from mobile phone videos and reports by local professionals. Probably, the same dolphin was there since 2017-2018 up to April 2020 (at least). In general, the solitary dolphin swims next to supply boats navigating along the port internal channel, and it rarely continues towards open sea. The dolphin plays with buoys and containment barriers, rubs itself against hulls, and bow-rides and jumps. There is no report of people swimming with this solitary dolphin, touching it, or offering it food in the Açu Superport. Thus, there seems to be no threats to the animal’s integrity locally.

摘要：独居行为是在少数群居性海豚物种中被观测到的一种罕见且特殊的行为模式。本研究记录了一只成年糙齿海豚（Steno bredanensis）在巴西东南部里约热内卢州北部阿苏超级港（21º49’S; 041º00’W）的独居行为。该海豚的相关数据来源于手机拍摄的影像资料以及当地专业人员的观测报告。据推测，同一只个体至少在2017-2018年至2020年4月期间持续栖息于此。总体而言，这只独居海豚会在港口内部航道航行的补给船旁巡游，极少前往外海区域。该海豚会与浮标及围障嬉戏、摩擦船体，并伴随乘首浪行为与跃出水面动作。在阿苏超级港内，尚无人类与该独居海豚一同游泳、触碰其躯体或投喂食物的相关记录。因此，目前来看该个体在当地未面临生存完整性相关的威胁。