This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Octopuses live short, lonely lives. Even the big ones only see a few years. And that usually means only one shot at creating the next generation—and they don't have time for parenting. So they up the odds of passing along their genetic legacy by making lots of babies, as in thousands and thousands of babies.
Female octopuses lay their eggs and painstakingly weave them together into strands. They then sit guard for weeks, months and sometimes as long as a year. During this time they don't seem to eat much, and their main preoccupation is keeping their eggs aerated and clear of algae, which they do by blowing water over them and cleaning them delicately with their suckers. At the end of the brooding period, nearly all of the octopus young hatch at once, creating a marvel for those lucky enough to witness it.
One diver in Puget Sound captured one impressive giant Pacific octopus (Enteroctopus dofleini) brood hatching on film last week. The water, about 30 meters below the surface, was filled with tiny baby octopuses, swimming up and away from their mother (seen tucked away in a den with additional strands of eggs). Although only millimeters long at hatching, these octopuses can grow to be adults weighing more than 15 kilograms and with an arm span of more than four meters.
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After leaving their egg casings, these hatchlings will swim toward the surface and join other small animals in a planktonic stage. Those that survive this dangerous phase will eventually settle back on the seafloor to feast on crabs—and search for their own mates.
The giant Pacific octopus can lay tens of thousands of eggs in her one and only brood. It only takes two or so octopuses out of each clutch to survive and reproduce to keep an octopus population steady. Baby octopuses, good luck out there.
Video courtesy of Laura James
Illustration courtesy of Ivan Phillipsen
