Rare octopus - oddball of the ocean

The rare species of cephalopod, which lives in the eastern Pacific, is also the only octopus to "kiss" while mating.

When it comes to good manners, the Pacific striped octopus may be the king of the ocean.

Unlike other cephalopods, which grab their prey and tackle it to the sea bed in a flurry of aggression, the creature gently taps its victims on the shoulder and startles them into its arms.

"I've never seen anything like it," said Roy Caldwell, professor of integrative biology at University of California, Berkeley.

"Octopuses typically pounce on their prey or poke around in holes until they find something. When this octopus sees a shrimp at a distance, it compresses itself and creeps up, extends an arm up and over the shrimp, touches it on the far side and either catches it or scares it into its other arms."

The rare species, which lives in the eastern Pacific, is also the only octopus to "kiss" while mating. Usually, male octopuses share sperm with females at arm's length, primed to flee should their mate get aggressive or hungry.

However, the Pacific striped octopus grasps its mate's arms sucker-to-sucker and copulates beak-to-beak, as if kissing. Unlike other octopuses, they also live in the same cavity for a few days and feed each other.

The larger Pacific striped octopus:

• Most octopuses live alone, coming together for brief and dangerous mating. Couples of this species can live together to mate for a few days in the same den or shell.

• Other male octopuses mate from a distance to avoid being cannibalised, but these octopuses mate entangled and beak-to-beak.

• While other females lay one batch of eggs and then die, the female of this species lives longer and produces eggs constantly.

• These octopuses clean out food waste from their dens.

• They twirl their arms like an old-time movie villain with a moustache.

• And they quickly learn that people mean food: when someone enters the room, they leave their dens and head to the top of the tank.