PhD candidate Krista Nicholson, who took the photos, said she had seen dolphins take part in an “octopus toss” before, but it was unusual to get pictures.
“It’s not unheard of for dolphins to do this, but it’s not a regular occurrence,” she said.
“We haven’t seen them (Mandurah dolphins) actually consume an octopus, so we are unsure whether this is foraging behaviour or if they are eating the octopus.
“But there are records from other parts of the world of dolphins playing with octopuses.”
Mrs Nicholson began her research project in Mandurah in January. She said Australia did not have a marine mammal protection Act and her research would seek to evaluate whether there was a need for one.
It was not unusual for Ms Nicholson to see groups of up to 18 individuals in coastal areas.
Mandurah dolphins were also known to get stuck in the shallows.
“It would be interesting to see if dolphins in this area have foraging specialisations and whether certain individuals spend more time than others in the rivers foraging,” she said.
“The animals that go up the river to fish must use different food-gathering skills.
“Maybe the food there is tastier?”
Part of her study will be to take tissue samples of Mandurah’s dolphins and see how closely they are related to the dolphins using the adjacent coastal areas.