Squid filmed using their ink clouds as smokescreen to catch prey

Ambushed! Japanese pygmy squid have been filmed releasing ink when hunting shrimp – using it both as a smokescreen and distraction.

“This is the first report that cephalopods use ink for predation,” says Noriyosi Sato of Aberystwyth University, UK.

In 2014, Sato and his colleagues collected 54 specimens of Japanese pygmy squid (Idiosepius paradoxus) from the waters of the Chita Peninsula in central Honshu, Japan, and transferred them to two lab aquaria.

They added live shrimp to the tanks and captured the squids’ feeding behaviour on video. The team observed 17 instances of the squid releasing ink as they began to attack the shrimp. In most cases, the shrimp were caught successfully

The team noticed two distinct tactics. In some cases, the squid ejected a cloud of ink into the space separating them from the shrimp, then cut straight through it and captured the prey. One individual released several such screens in a sequence as it moved ever closer to its victim. The team thinks the cloud serves as a smokescreen that prevents the prey from seeing the attacker’s movement.

Other sneaky hunters released puffs of ink away from the shrimp and attacked them from a different, unexpected angle. Sato says these clever manipulators are using the ink as a decoy that attracts and diverts the prey’s attention from the direction of the attack.

“This means they use ink as a tool, and it is a concrete example that squid have intelligence,” he says.

Squid and other cephalopods usually release clouds of ink when attacked, to obscure a predator’s view and jet away.

“It is exciting, because it is a very familiar behaviour, and they are using it in a totally novel way,” says Jean Boal of Millersville University in Pennsylvania.

But more research is needed to investigate whether the behaviour is learned or innate, and how common it is among squid, she says.