THEY may not have any hands or knives, but Australian dolphins make great calamari chefs.
Scientists have discovered the marine mammals can perform a series of sophisticated manoeuvres that rid a cuttlefish of its ink and bone to produce a tasty soft meal.
A wild female bottlenose dolphin was observed repeatedly using the same steps to prepare cuttlefish cuisine in her kitchen in the waters of Spencer Gulf in South Australia.
"It’s a sign of how well their brains are developed. It’s a pretty clever way to get pure calamari without all the horrible bits," the curator of molluscs at Museum Victoria and a member of the research team, Mark Norman, said.
First the dolphin herded a cuttlefish out of the weeds and onto a sandy patch of sea floor.
Standing on her head, she pinned it down with her snout. Then, with a powerful flick of her tail, she killed it with a rapid downward thrust.
Dr Norman said the black ink that cuttlefish squirt out to defend themselves was toxic. "It’s pretty horrible stuff."
To get around this problem the dolphin lifted the corpse up and whacked it with her snout "like a cricket bat" as it floated around until all the ink came out.
"Cuttlefish also have a big, hard surfboard of cuttlebone inside," he said.
To avoid this unpalatable part, the dolphin returned the cuttlefish to the sea floor and forced it along the sand to scrape off its skin until the cuttlebone popped out – and then dinner was ready.
The same female was seen preparing cuttlefish in 2003 and 2007, the researchers report in the science journal, PLoS One .
But the behaviour was likely to be widespread. "Repeated observations of clean cuttlebones bobbing to the surface in association with passing pods of dolphins suggest that some or all of this behavioural sequence is not restricted to a single individual dolphin," they concluded.
Female bottlenose dolphins have also been seen using sponges as tools in Western Australia, to protect their snouts as they probe the sea floor for food.
In the first evidence of cultural learning among dolphins, a study in 2005 showed that mothers teach their daughters the trick of breaking off the sponges and wearing them.
Dr Norman said it was not yet known whether the mothers also trained their daughters to become cuttlefish chefs.