Call it extreme parenting: Scientists announced the discovery of a deep sea octopus mom that faithfully guarded the same clutch of eggs for a record-breaking 4-1/2 years.
The long brooding period represents the far end of an underwater parenting spectrum. On the opposite end lies the "broadcast spawn" strategy, when an animal releases hundreds of thousands of eggs into the water and hopes for the best. Most of those eggs and juvenilles get gobbled up by predators, but because there are so many of them, a few do make it to adulthood.
What makes this ocotopus's herculean act of parenting all the more amazing is that during those 4-1/2 years that she is protecting her eggs, she does not appear to eat.
But other than that, she just sits there. The lack of eating takes a toll on her health, of course. Her muscles atrophy. Her body gets smaller. Her color gets paler. And when her babies finally do hatch as fully developed, fairly substantial octopuses about 4 centimeters long each, the mom wastes away entirely. Her work is complete.
This lengthy brooding period was only discovered in the last few years when researchers from the Monterey Bay Aquarium Research Institute got lucky and located a Graneledone boreopacifica just weeks after she laid her eggs.
Their findings were published in a paper published Wednesday in PLOS One.
The research began in April 2007, when the team took a remotely operated vehicle (ROV) out for a spin in the Monterey Submarine Canyon and came across an isolated rocky outcropping on the ocean floor about 4,600 feet down.
Deep-sea octopuses need to find rocky slopes at the bottom of the ocean to which to attach their eggs, and scientists had seen octopuses guarding their eggs in this spot before. This time, however, the slope was octopus-free, although the researchers did notice an octopus moving over the sandy floor toward the hard surface.
That meant the octopus had laid those eggs within the ROV's last pass, and the research team now had the rare opportunity to measure the length of a Graneledone boreopacifica brooding period from its very beginning.
Over the next 4-1/2 years the ROV returned to the same spot 18 times -- about once every two months. They watched as the egg capsules more than doubled in size from 1.5 centimeters in length to 3.3 centimeters. In that time they never saw the mother leave her eggs, and they never saw her eat a morsel of food.
All species of octopus keep watch over their eggs, but the typical brooding time is usually closer to a few months, rather than several years. Because Graneledone boreopacifica lives in such a chilly environment where the water is about 35 degrees Fahrenheit, scientists anticipated that their metabolic activity and life cycle might be slowed down. However, they did not anticipate it would be slowed down so much.
Part of what makes this study so surprising is that octopuses are in general are not very long lived creatures -- most of them have a life span of just two to three years.
Although it is tempting to anthropomorphize this deep-sea octopus mom, to marvel at the maternal sacrifice that has her wasting away while she watches over her eggs until her death just after they hatch, Voight cautions against it.
"It is not just the female giving her all," she said. "It is not a maternal thing. It is just that their lives are programmed to run fast and end early."