Valentina Cippà

It is not known to what extent botos (Inia geoffrensis) living in the Brazilian Amazon associate socially with one another. Their mating patterns have remained cryptic until now due to the difficulty of observing copulations. Inia is one of the most sexually dimorphic cetaceans for size, and male botos are known to engage in male-male conflict. Adult males, and occasionally sub-adult males, have been observed carrying various inedible objects, such as sticks and vegetation, for the apparent purpose of sexual display. It has been suggested that object-carrying by adult males is for the females’ benefit and is triggered by the number of females or the large number of males in a group. My Master’s project aims to shed light on Inia social structure and to establish parentage using microsatellite data. I will test the hypotheses that males who have been observed carrying objects have a higher reproductive success than “non-carriers”, reinforcing the idea that object-carrying is a socio-sexual display. Male body size will also be compared with reproductive success, with the idea that a larger body size would give an advantage during male-male competition for mates.