You’d think it would be difficult to miss a giant. But it seems that one such behemoth of the ocean has in fact been hiding right under our noses, and it turns out that fishermen have been hauling it up from the deep for a long time.
Tipping the scales at up to 71 kilograms (156 pounds), the giant Pacific octopus is by far the largest species of octopus known to science. Living in the cold, oxygen-rich coastal waters of the northern Pacific, ranging from southern California up to Alaska and down to the Korean Peninsula, the cephalopods can grow to impressive sizes as they feed on shrimp, crabs, and lobsters.
With such a widely distributed species, it’s perhaps unsurprising that the giant Pacific octopus is actually (at least) two separate species. In fact, the idea that there are two distinct species has been hinted at since 2012. Back then, researchers carried out a small genetic study of the giant octopuses that hang around off the coast of Alaska.
They found that the DNA samples collected showed that there were two genetically distinct populations living in these frigid waters. Yet because these samples were taken by snipping off little pieces of the unfortunate cephalopods' tissue, there was no way of confirming whether or not the genetic differences tallied up with distinct physical differences that might help confirm they were indeed separate species.
A few years later, two researchers set out to settle it. By collecting live octopuses caught as bycatch by shrimp fishermen in Prince William Sound, Alaska, the team could not only collect more DNA samples, but also morphological data regarding external appearance.
And indeed, they found that the genetic differences picked up by the earlier study and confirmed by their newer one did match up with two distinct looking cephalopods caught in the shrimp pots.
They found that in addition to the standard giant octopus, there was another form that has a frilly ridge running down its mantle, as well as frilly fringing around its eyes that looks a little like eyelashes. Understandably, this new species has been named the frilled giant Pacific octopus.
While new to science, the creature is certainly not new to those who make a living in these waters. The researchers found that around a third of all giant octopuses caught as bycatch are most likely the frilled variety, suggesting it is not uncommon. How prevalent it is, however, is hard to discern, as scientists suspect that it inhabits deeper water than the more well-known species, which is why it had not been identified until now.