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Science Coronavirus Coverage U. Travel A road trip in Burgundy reveals far more than fine wine. Travel My Hometown In L. Travel The last artists crafting a Thai royal treasure. Subscriber Exclusive Content. Why are people so dang obsessed with Mars? 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. 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.
Illustration courtesy of Ivan Phillipsen. Their skin pales and they lose muscle tone, even beyond what you would expect to see in a starving octopus. Wang, who has made pets out of some of the octopuses in the lab, said, "This is troubling to even witness in the lab, because from a human perspective they look like they're self-mutilating.
It's just very, very strange behavior. Wang collected the optic glands from octopuses at each phase and sequenced the RNA transcriptome of each. RNA carries instructions from DNA about how to produce proteins, so sequencing it is a good way to understand the activity of genes and what's going on inside cells at a given time.
During the non-mated phase when females were actively hunting and eating, they produced high levels of neuropeptides, or small protein molecules used by neurons to communicate with each other that have been linked to feeding behavior in many animals.
After mating, these neuropeptides dropped off precipitously. As the animals began to fast and decline, there was more activity in genes that produce neurotransmitters called catecholamines, steroids that metabolize cholesterol, and insulin-like factors.
Wang said finding activity related to metabolism was surprising because it's the first time the optic gland has been linked to something other than reproduction. Just how these molecular and signaling changes cause the different behavioral changes is unclear though. Females in the early stage of brooding continued to eat but didn't actively seek out food. This could mean that the neuropeptides affect the amount of energy the octopus expends to find prey.
Certain muscles may begin to deteriorate so the octopus physically can't hunt or digest food. The increased steroid and insulin production could be targeting reproductive tissues that promote maternal behavior, or they could be directing energy away from digestion and feeding. The scientific jury is still out as to why these clever, resourceful creatures meet such an ignominious end, but there are several theories.
Octopuses are serious cannibals, so a biologically programmed death spiral may be a way to keep mothers from eating their young. The above looks like a poetic tragedy, it looks good for some type of story or romance but it happens to every female octopus anywhere in the world that reproduces successfully.
Came across this while researching if octopuses take care of their young, as caring for young has been demonstrated to have played a role in the continued development of early humans intelligence. Since octopuses do not care for their young in the same way as mammals, it would be interesting to study how their higher level of intelligence developed without the vertical transfer of knowledge. Perhaps female octopuses give chemical signals to their eggs to speed up or slow down their development.
This could be tested in aquaria if mother octopuses are encouraged to look after eggs there and the water round them is regularly analysed chemically. Perhaps young octopuses are flexible in when they hatch. While its mother can defend a young octopus its best survival strategy is to stay in its egg shell and continue its development there protected by its mother. After its mother weakens the best survival strategy for the young octopus is to hatch so it can react to predators and to be dispersed in the plankton.
The mother disperses the young and the young hatch. This could be tested in aquaria if eggs from one mother octopus are marked and moved to the den of another mother octopus where the eggs are slightly older or slightly younger.
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