The team at the Mandurah Dolphin Research Project noticed that after mating season was over, the male Bottlenose dolphins were ‘mounting’ and ‘having genital contact’ with each other.
‘These dolphins, all but three of them juveniles, organised themselves in four subgroups in which they were observed engaging in socio-sexual behavior that included mounting and genital contact between individuals,’ Murdoch University’s Krista Nicholson told the Mandurah Mail.
‘The subgroups joined, frequently forming a large group, and then split again in different group compositions.’
She said that this behaviour was typical of Bottlenose dolphins, which are usually found in tropical oceans and warm waters around the world.
Scientists who have extensively studied the Bottlenose dolphin population in Shark Bay, Western Australia, have observed bisexual behaviour and evidence of a social heiraechy.
‘Apart from homosexual behavior, males, unlike females, in Shark Bay have also been recorded to perform synchronous displays,’ Ms Nicholson explained.
She said that in Shark Bay, two male dolphins are more likely to mate for life than two female dolphins or two dolphins of different genders.
Unsurprisingly, homosexual behaviour also plays a role in establishing dominance between male dolphins, helping to cement ‘social bonds’.
The research team headed by Ms Nicholson were ‘excited’ to record the similarities between Mandurah and Shark Bay dolphins.
Observing another group of dolphins in the same area exhibiting the same behaviour will further help their research into how and why the homosexual; behaviour occurs, according to NewsWeek.
Dolphin expert Janet Mann, who has spent decades at Shark Bay observing dolphins, suggests in her book that homosexual contact between male dolphins is ‘practice’ for mating season.
‘Our understanding of the social structure and relationships in a larger context would suggest that male-male social-sexual interactions are…practicing courtship behaviours for adulthood.’
Ms Mann also suggest that the behaviour serves multiple functions, including ‘fitness’ and ‘alliance formation’.