We analysed the behaviours, vocalisations and hormones of Australian fur seals and here is what our study found:
There was an increase in the production of the bark call during the onset of the breeding season (August through to October).
Faecal testosterone levels peaked in September, coinciding with the increase in the bark call.
Guttural threat calls were rarely heard throughout the year, but peaked in August. This call was was associated with specific behaviours that were produced during more intense fighting interactions.