Ravignani, A. (2018) Spontaneous rhythms in a harbor seal pup calls. BMC Research Notes 11(3), pp.1-4. Abstract. Timing and rhythm (i.e. temporal structure) are crucial, though historically neglected, dimensions of animal communication. When investigating these in non-human animals, it is often difficult to balance experimental control and ecological validity. Here I present the first step of an attempt to balance the two, focusing on the timing of vocal rhythms in a harbor seal pup (Phoca vitulina). Collection of this data had a clear aim: To find spontaneous vocal rhythms in this individual in order to design individually-adapted and ecologically-relevant stimuli for a later playback experiment.The calls of one seal pup were recorded. The audio recordings were annotated using Praat, a free software to analyze vocalizations in humans and other animals. The annotated onsets and offsets of vocalizations were then imported in a Python script. The script extracted three types of timing information: the duration of calls, the intervals between calls’ onsets, and the intervals between calls’ maximum-intensity peaks. Based on the annotated data, available to download, I provide simple descriptive statistics for these temporal measures, and compare their distributions. The article is open access and freely available (including scripts and raw data) at: https://bmcresnotes.biomedcentral.com/articles/10.1186/s13104-017-3107-6 Kind regards, Andrea Andrea Ravignani Research Dpt., Sealcentre Pieterburen Max Planck Inst. for Psycholinguistics AI-Lab, Vrije Universiteit Brussel ravignani.wordpress.com