Mother Octopus Cares for Her Eggs Without Eating for a Record 4.5 Years in the Deep Sea

Birds and salmon brood their eggs for just a few weeks, so it's hard to imagine any animal brooding its eggs for four-and-a-half years. But that's exactly what one deep-sea octopus has done in the depths of Monterey Canyon off of the coast of California. The animal has managed to not only keep her eggs clean and guard them from predators, but has also survived for years on little to no food.

Every few months for the last 25 years, a team of researchers have performed surveys of deep-sea animals at a research site called Midwater 1 in Monterey Canyon. In 2007, though, the researchers discovered a female octopus clinging to a rocky ledge just above the floor of the canyon, about 4,600 feet below the ocean surface. The species, known as Graneledone boreopacifica, was guarding a brood of eggs that slowly grew larger over the years.

Over four-and-a-half years, the mother guarded her eggs in the same location. She slowly lost weight and her skin became loose and pale, yet she never seemed to leave her eggs or even eat anything. In fact, she didn't show the slightest interest in small crabs and shrimp that crawled or swam by as long as they didn't bother her eggs.

Then, in 2011, the eggs finally hatched. The researchers found the rock ledge where the mother octopus had been to be abandoned with only the remnants of egg capsules. In all, the scientists counted the remains of about 160 eggs.

"This research demonstrates how little we know about life in the deep-sea and life generally," said Brad Seibel, one of the researchers, in a news release. "From shallow-living species we have developed limited and limiting ideas about the capabilities of animals."

More specifically, this long brooding behavior is particularly unusual. It presents an evolutionary challenge for animals, such as octopus, which generally don't live very long. Yet the behavior can produce hatchlings that are highly developed which may give them the advantage that they need in order to survive.

In addition to having the longest brooding time of any animal, though, this octopus may just be one of the longest lived cephalopods in existence. While most shallow-water octopuses and squids live just a year or two, this one survives for at least five.

"The ultimate fate of a brooding female octopus is inevitably death," write the researchers. "But in this first example from the deep sea, brooding also confers an extension of adult life that greatly exceeds most projections of cephalopod longevity."

The findings are published in the journal PLOS One.