Dear colleagues, My paper on interactive call timing in a harbor seal pup has just been published in the Journal of Comparative Psychology. The paper is available on the journal webpage: http://dx.doi.org/10.1037/com0000160 . If you would like to obtain a PDF, do not hesitate to contact me at: andrea.ravignani@gmail.com . Kind regards, Andrea Ravignani, A. (2018). Timing of antisynchronous calling: A case study in a harbor seal pup (Phoca vitulina). Journal of Comparative Psychology. Advance online publication. http://dx.doi.org/10.1037/com0000160 Alternative mathematical models predict differences in how animals adjust the timing of their calls. Differences can be measured as the effect of the timing of a conspecific call on the rate and period of calling of a focal animal, and the lag between the two. Here, I test these alternative hypotheses by tapping into harbor seals’ (Phoca vitulina) mechanisms for spontaneous timing. Both socioecology and vocal behavior of harbor seals make them an interesting model species to study call rhythm and timing. Here, a wild-born seal pup was tested in controlled laboratory conditions. Based on previous recordings of her vocalizations and those of others, I designed playback experiments adapted to that specific animal. The call onsets of the animal were measured as a function of tempo, rhythmic regularity, and spectral properties of the playbacks. The pup adapted the timing of her calls in response to conspecifics’ calls. Rather than responding at a fixed time delay, the pup adjusted her calls’ onset to occur at a fraction of the playback tempo, showing a relative-phase antisynchrony. Experimental results were confirmed via computational modeling. This case study lends preliminary support to a classic mathematical model of animal behavior—Hamilton’s selfish herd—in the acoustic domain. (PsycINFO Database Record (c) 2018 APA, all rights reserved) Andrea Ravignani Research Dpt., Sealcentre Pieterburen AI-Lab, Vrije Universiteit Brussel ravignani.wordpress.com