In observations from 2007 to 2011, deep-sea diving researchers at Monterey Bay Aquarium Research Institute (MBARI) discovered that the female Graneledone boreopacifica guards her eggs for 53 months — that’s almost four and a half years — the longest brooding period ever recorded.
Seen guarding the same clutch of 160 eggs in the same location, 1,400 meters deep in California’s Monterey Submarine Canyon, she was identified by her distinctive scars during each of the researchers’ 18 visits. With every sighting, they observed that the octopus “looked weaker and more bedraggled,” likely never leaving her eggs unattended. Slate lays out the timeline:
Every few months the researchers checked in on the brooding mama while she gradually deteriorated. She started out with a “highly textured and pallid purple” mantle, but it paled to near whiteness once she began guarding her clutch. Her plump, round body gradually deflated, her skin went slack and lost its texture, her eyes grew cloudy and her tentacles lost their color. Tasty crabs and shrimp ventured by, but she just shooed them away from her eggs when they got too close, never having a snack. The scientists even offered her pieces of crab with the vehicle’s robot arm, but she ignored them. If she ever ate, they never saw it.
At 40 months, three quarters of the way into her brooding, the outlines of the baby octopuses inside their eggs were clear. By the last time the researchers saw her in September 2011, the eggs had grown to the size of Brazil nuts. On their 18th dive a month later, she was gone, leaving behind about 160 empty egg capsules. She had spent 53 months brooding her eggs, almost four times the longest octopus brooding time previously recorded…
There are only a few animals that carry their young or care for their eggs for such long periods. Elephant gestation lasts nearly two years, “frilled sharks carry their embryos up to 42 months,” and the alpine salamander carries 2-4 offspring internally from two to four years, depending on the altitude. Scientific American reports that a female Bathypolypus arcticus, another kind of deep-sea octopus, protected its clutch for 14 months in the lab.