At the Bottom of the Ocean, Octopus Moms Cling to Their Bad Decisions

By Elizabeth Preston | April 26, 2018 8:17 pm

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Parents may feel guilty when they use television to keep their kids quiet, or give in to a demand for cookies. But most of us are doing a better job than these octopus mothers. Scientists found them clustered on the sea floor, trying to grow their young in a warm bath that will certainly kill babies and moms alike.

The mothers were doomed to begin with. After mating, most female octopuses choose a spot to glue down a batch of eggs. Then they park themselves on top of those eggs and give up eating or moving. The mother stays there, guarding her developing eggs and washing them in seawater, until she wastes away. Researchers observed one deep-sea octopus mom brooding the same batch of eggs for four and a half years.

On expeditions in 2013 and 2014, other researchers explored a rocky formation about two miles under the Pacific, near Costa Rica. They sent down both crewed and robotic vessels to investigate warm water that intermittently seeps from the rock here. The fluid that leaks out “shimmers upon mixing with seawater,” the scientists write.

When their cameras got close to the rock, the researchers were startled to see several hundred octopuses. Some were swimming or drifting upright; many were clustered together with their bodies tucked into balls. These clusters turned out to hold dozens of female octopuses brooding their eggs alongside each other, in a kind of nursery.

The animals belonged to a poorly understood genus called Muusoctopus. Most were a dull purple color, with large eyes and relatively short arms. Beneath their balled bodies, the researchers spotted clumps of white, finger-shaped eggs standing upright.

The warm bath these mothers had settled into might seem luxurious. The water temperature outside the flow was only 1.8 degrees Celsius—barely above freezing—while inside the flow it ranged from 2.5 to 12.3 degrees Celsius (as high as 54 degrees Fahrenheit). Warm water should make the octopus embryos develop more quickly inside their eggs. But, the researchers found, this warm water seep held only half as much oxygen as the regular seawater.

The lack of oxygen was taking a visible toll. Octopuses within the warm flow were breathing much more rapidly than others. When the scientists were able to examine some of the eggs closely, they saw no signs that embryos were developing inside. They expect all the eggs to die.

How did these octopus moms land themselves in such a bad situation? It seems unlikely that they all read the same misguided parenting book.

Instead, the researchers suspect the doomed mothers are only a fraction of a much larger octopus population here. Some females may lay their eggs on this spot during a time when the warm water isn’t flowing. By the time it starts up again, they’ve already cemented their broods to the rock, and it’s too late to move.

The researchers think there are many more octopuses out of sight. Inside the crannies of the rocky formation, perhaps, they’re making parenting decisions that will at least keep their young alive.


Image: Phil Torres and Geoff Wheat

MORE ABOUT: Animals, Evolution, Ocean
  • John Thompson

    They are not clinging to their bad decisions, they are protecting their offspring.
    It’s normal for most creatures who raise their young to go to great lengths to defend their offspring – perhaps that doesn’t sit so well with those that are pro abortion, which is radically opposite of nature – but it’s the way and why we are here now.
    Yes, human mothers (and fathers) also defended their offspring in the same manner in the past. Thank goodness they did!

    • TLongmire

      Imagine the effort involved in spending 40000 hours of your existence clinging on to hope of survival only to be forsaken. Seems wrong

    • Spacetrucker

      “It’s normal for most creatures who raise their young to go to great lengths to defend their offspring – perhaps that doesn’t sit so well with those that are pro abortion, which is radically opposite of nature”
      You do realize that many animals give birth to two offspring and the stronger kills the weaker while the parent watches. Perhaps that doesn’t fit your idea of pro life but it’s true. I’m sure that you’ve adopted an unwanted child though and are a person of action as opposed to words.

    • Arishia

      I watched an Eagle whose mate died incubate eggs in the snow for four days without getting up to find food or to exercise, only to then give up the clutch and save its own life.

  • Jon Brooks

    I’ve been saying this for years, animal mothers are not exempt from our child endangerment laws just because they are animals. Animals are pretty damn smart. All signs of abuse in the animal kingdom should be reported investigated to the nearest social services office.



Like the wily and many-armed cephalopod, Inkfish reaches into the far corners of science news and brings you back surprises (and the occasional sea creature). The ink is virtual but the research is real.

About Elizabeth Preston

Elizabeth Preston is a science writer whose articles have appeared in publications including Slate, Nautilus, and National Geographic. She's also the former editor of the children's science magazine Muse, where she still writes in the voice of a know-it-all bovine. She lives in Massachusetts. Read more and see her other writing here.


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