Forget a bouquet of flowers or box of chocolates, it seems sea sponges are all the rage amongst West Australian male dolphins looking for a possible mate.

University of Western Australia researchers have captured unusual evidence of adult male Australian humpback dolphins offering "gifts" to their female counterparts, in an apparent effort to convince them to mate.

The study observed an interaction between a male, female and her calf off the WA coast where the potential dating technique was used.

"The male dolphin dived down to remove a large marine sponge fixed to the seafloor, balanced it on his beak and pushed it toward the female," the report said.