Mother of the Year in the animal kingdom could go to a deep sea octopus who spent at least four and one half years fearlessly guarding and caring for her eggs before they hatched.
The effort breaks the world record for egg brooding and is documented in the latest issue of PLoS ONE.
Bruce Robison, a researcher at the Monterey Bay Aquarium Research Institute, and his colleagues spotted the vigilant deep sea octopus mother in May 2007 during regular surveys at a Pacific Ocean site in the Monterey Canyon called "Midwater 1." The female Graneledone boreopacifica was clinging to a rocky ledge just above the floor of the canyon about 4,600 feet below the ocean surface.
Over the next 4.5 years, the researchers dove to this exact same site 18 times, according to the paper. During each visit, they saw the same octopus. She was easy to spot, as she had distinctive scars on her body, possibly sustained while fighting off predators hoping to snatch her eggs.
The mother octopus never moved from her spot during that entire time. She did not even feed or show interest in food, such as small crabs and shrimp, which would float by every so often.
She was solely focused on watching over her eggs and bathing the eggs in fresh, oxygenated seawater to keep them from being covered with silt or debris.
As the years passed, her translucent eggs grew larger and the researchers could see young octopuses developing inside. Over the same period, the female gradually lost weight and her already damaged skin became loose and pale.
The last time the researchers saw the brooding octopus was in September 2011. When they returned one month later, they found that the female was gone. As they wrote, “the rock face she had occupied held the tattered remnants of empty egg capsules.” Based on these remains, they speculate that she was brooding 160 eggs!
Robison and his colleagues explained that the eggs develop more slowly in cold temperatures. The site is usually about 37 degrees Fahrenheit. Young of this species also emerge from the eggs as fully formed miniature adults.
"The trade-off within the reproductive strategy of deep-living octopods is between the mother's ability to endure a long brooding period and the competitiveness of her hatchlings," the researchers explained. "Graneledone boreopacifica produces hatchlings that are very highly developed, which gives them the advantage of a high potential for survival."
As for what happened to the mother, "The ultimate fate of a brooding female octopus is inevitably death," the researchers wrote, "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."
It is possible that other deep sea animals could break even this female's impressive egg brooding record in the future. Close to the same league as this octopus is a species of mysid, a shrimp relative that is abundant in depths of Monterey Canyon. The mysid carries eggs for 20 months and goes without food the whole time.
The scientists say that it's important to understand such behaviors, since they affect how human activities could impact these animals. For example, accidental capture of one of these moms could lead to a dangerous reduction of the population, requiring years to recover. Preservation of the habitat, the climate and more are also key to the success of the young.
Life seems hard enough for these mothers. Hopefully, aside from studying and admiring them, we can leave them alone.
Photo: a Graneledone boreopacifica in the Pacific Ocean. Credit: NOAA/Monterey Bay Aquarium Research Institute