Why Octopus Mothers Stop Eating and Die After Laying Their Eggs

Octopuses are among the most intelligent invertebrates, able to solve puzzles, change color, and regrow arms. Yet in most species a mother’s life ends in a strange sequence that biologists call the death spiral.

What actually happens to a mother octopus?

After she lays her eggs, she guards and tends them, fanning water over them and keeping them clean. Then she stops eating. In the California two-spot octopus studied at the University of Chicago, the fast lasted about 11 days before a rapid decline began, according to a Live Science report on the 2018 study: the mothers groomed themselves obsessively, became agitated, and in some cases damaged their own arms and sucker tips. Their skin paled and sank around the eyes. By the time the eggs hatched, the mother was dead. Male octopuses in these species also die not long after mating.

What controls it?

A pair of small organs called the optic glands, which sit between the eyes and work something like the pituitary gland in mammals. The key evidence is almost fifty years old. In 1977 the Brandeis psychologist Jerome Wodinsky removed the optic glands from brooding Caribbean two-spot octopus mothers. They abandoned their eggs, resumed feeding, and lived for months longer, according to a University of Chicago account. The conclusion was that the gland secretes some kind of self-destruct signal. What it was remained unknown for decades.

What did the recent studies find?

In 2018, Z. Yan Wang and Clifton Ragsdale at the University of Chicago sequenced which genes were switched on in the optic glands of California two-spot octopuses at each stage of maternal decline. As the mothers began to fast, genes that metabolize cholesterol and produce steroid hormones became more active, the first time the gland had been linked to anything other than reproduction.

In 2022, Wang, Ragsdale, and chemists at the University of Illinois Chicago analyzed the chemicals the gland produces, in a paper in Current Biology. They found three biochemical pathways that increase steroid hormones after reproduction, according to the University of Washington’s summary. One produces pregnenolone and progesterone, steroids associated with pregnancy. Another produces cholesterol-related molecules that are intermediates for bile acids. The third raises levels of 7-dehydrocholesterol, a precursor to cholesterol. Some of these pathways are the same ones that make cholesterol in mice and other mammals.

The researchers describe this as a step, not the whole answer: the gland’s shift sets off changes downstream that lead to the mother’s behavior and death, and Ragsdale noted that the progression of odd behaviors might reflect two, three, or four separate processes.

Is there a human connection?

A suggestive one. The University of Chicago report notes that elevated 7-dehydrocholesterol is the hallmark of a rare human genetic disorder, Smith-Lemli-Opitz syndrome, in which children show severe developmental and behavioral problems, including repetitive self-injury that the researchers found reminiscent of octopus end-of-life behavior. The point is not that the conditions are the same, but that disrupting cholesterol production has grave effects in very different animals.

Why would evolution build an animal that dies after reproducing?

This is the open question. Semelparity, reproducing once and then dying, appears across the animal world, from salmon to some insects. For octopuses, one proposed explanation is that a mother’s death ensures she will not consume her young, according to the Live Science report on the 2018 study. Octopuses are cannibalistic and would otherwise be a threat to their own hatchlings. Another is that the mother’s resources are better spent on one large, well-guarded clutch than on surviving to breed again. Neither has been tested directly.

Do all octopuses do this?

No. The lesser Pacific striped octopus breeds multiple times and does not self-destruct after mating, according to the University of Washington report. Wang planned to study its optic gland next to see how it avoids the spiral. That comparison may show what the self-destruct system is for, and what switches it off. See is any animal immortal and do animals understand death.

This is general educational information, not medical advice. Research in this area moves quickly and this page reflects sources available at the date shown; check the date and the sources before relying on a specific claim.