Very large and unexplained variation in mating calls of male harbour seals

What is it about?

Underwater mating calls from male harbour seals, so-called roars, were recorded from three different breeding sites in Southern Scandinavia. These were in the Danish Wadden Sea, the Limfjord, Northern Denmark and Kalmarsund, Southern Sweden. Analysis of acoustic parameters of the calls showed very large varation both within and among recording locations. Even through the population in Kalmarsund is believed to have been genetically isolated from the other populations for several thousand years, the calls were not more different from calls from the other recording locations than recordings from two consequtive years at the same location (Limfjorden). This could point to a very large variation among calls from individual males, but leaves it completely open what acoustic parameters of the calls are important for the call's role in mating.

Featured Image