First time filming the moment an octopus shoots rocks at predatory fish

Filmmakers have captured the moment an octopus fires a rock bullet at a predatory fish while hiding in a clamshell, like a sniper.

Footage from Netflix's "Our Ocean" shows a coconut octopus ( Amphioctopus marginatus ) , also known as a veined octopus , firing tiny stones from its siphon, a structure that octopuses use to swim and navigate, at fish swimming by, according to Live Science .

Octopus hiding in a shell shoots rocks at fish swimming by. (Photo: Netflix).

'We couldn't believe it,' said Katy Moorhead, the show's production assistant and field director. 'It was shooting rocks at the fish with a siphon. No one had ever filmed a coconut octopus using a siphon as a weapon before.'

The crew filmed the clip 30 feet below the surface of the ocean in Southeast Asia. Initially, the filmmakers were investigating the impact of plastic pollution on the ocean, focusing on a solitary octopus living on a trash-strewn seafloor. But when they reviewed the footage, they realized they had captured a completely new behavior.

The team returned to the octopus to find out if it was a spontaneous behavior or if the animal had figured out how to use the siphon like a gun to deter predators . Roger Munns, the show's director of photography, spent 110 hours with the octopus over three weeks, eventually capturing the behavior in detail. It collects rocks and debris, stores them, and then fires them.

The rocks were fired so fast that they could only be seen in slow motion. "Faced with a large fish in a situation where it was exposed, the octopus shot it straight in the face ," said production manager James Honeyborne.

Coconut octopuses live in shallow water in sandy mud. They live throughout the Indian Ocean, emerging from their hiding places at dawn and dusk to feed. They often hide in shells and coconut shells, closing their two shells together to form a shield. When not in use, they pull the shells along, stack them on top of each other, and retreat inside, sticking out their arms to move along the seafloor.

Researchers are analyzing the coconut octopus's stone-throwing behavior to better understand why it does it. According to producer Jonathan Smith, the fish clearly panics and swims away, suggesting it is an effective deterrent to predators.