- Recent study shows humpback male dolphins presenting marine sponges to females as a gift
- Male bottle-nose dolphins were also observed to be helping each other as "wingmen"
(CNN)Romance isn't dead yet -- at least not in waters off the western coast of Australia.
Scientists have recently observed humpback male dolphins in the region presenting females with large marine sponges in the hope of impressing them.
They also observed male humpback dolphins acting as "wingmen" for each other-- this type of male cooperation is unusual in dolphins given that paternity can't be shared.
This is the first time this level of social complexity has been observed in dolphins.
Not just foraging
While previous research has shown bottle-nose dolphins using sponges and sometimes shells as foraging tools, this was clearly different.
"This is a sexual display involving object carrying by humpback dolphins," said Simon Allen, the lead author of a study on the phenomenon that was released last month.
The research was carried out across the north-western Australian coastline, with sites in Coral Bay, the North West Cape, Dampier Archipelago, Cygnet Bay and Cone Bay.
"This is incredibly rare in mammals, except of course, in our own species," Allen, from the University of Western Australia, told CNN.
There are three possible reasons for this behavior, he said: "It's gift giving, it's a signal of his fitness (so) quality as a mate, or it's a threat to coerce her into mating with him."