Daily Archives: September 11, 2015

The crafty larger pacific striped octopus

The larger pacific striped octopus

The larger Pacific striped octopus has not been studied much or even described scientifically, so it has no scientific name yet; but it is proving to be an interesting critter. Caldwell, Huffard, and colleagues reported August 12 in PLOS ONE that these creatures in their lab behave differently from other octopuses in many ways.

Octopuses eat a lot of crustaceans. The larger pacific striped octopus is no exception in this regard. It’ll pounce on a crab and rip it apart with its tentacles and beak. But not so with a shrimp. This octopus plays schoolyard tricks on shrimps.

When a hungry larger pacific striped octopus comes upon a shrimp, it stands a little bit apart so the shrimp won’t notice it. Then it stretches out one tentacle and sneaks it over the shrimp to tap the prey on its shell, like a schoolboy playing a prank on a friend. But this is no prank; it startles the shrimp into running directly into the waiting arms of the predator.

Females live longer

Another unusual thing is that a female of this species keeps on living after guarding her eggs until they hatch. In most octopus species, a female tends her eggs constantly, refusing to even eat or mate for many months until the eggs hatch. Then she dies of exhaustion and starvation. I always felt sorry for those octopus mothers, though they may feel fulfilled as they fizzle out. Who knows? Not so the female of the larger pacific striped octopus. She lives on to produce more eggs.

Sex is different, too. They do it face to face, beak to beak, all tangled up together. Other kinds do it  couple of different ways.

In all octopuses, the male sex organ is one of his arms. Always the same one. He places sperm into the female with the tip of one tentacle. But it’s how they do this that’s different. One species, for example, mates from a distance:

In an Indonesian octopus species, Caldwell’s former student Christine Huffard of the Monterey Bay Aquarium Research Institute discovered males hunkered in their dens sending an arm across the seafloor into the den of the female next door.

She’s maybe a yard away from him, hidden all alone in her own private little den made of pebbles, sand, or a shell. This method doesn’t seem to do much for her. In fact, she seems to get bored with it sometimes.

On occasion, such females leave their dens on some octopus errand, dragging the male along by his mating arm.

No wonder. It’s “you stay in your room, I’ll stay in mine, and I’ll hand you a packet of sperm under the door.” Maybe he’d be better off bringing her chocolate and flowers.

larger pacific striped octopus

Larger pacific striped octopuses mate above. The darker one on the right is male; the lighter on the left, female.

Larger pacific striped octopuses not only mate face to face, but they match up all eight tentacles as they do so, as if they want as much skin contact as they can get. Some of them even share a den for a day or two afterward, which is highly unusual for such solitary animals as octopuses. And a female with a clutch of eggs will sometimes turn her back on them long enough to mate again.

These are fascinating animals that deserve much more study, a scientific name, and a shorter, snappier common name than “larger pacific striped octopus.”