Deep-Sea Octopus' Egg-Brooding Period Breaks Record!
Robins sit on their eggs for about two weeks after they are laid. Male seahorses usually carry eggs for 9 to 45 days. Deep-sea octopuses? Four and a half years!
Researchers at the Monterey Bay Aquarium Research Institute (MBARI) have observed this unique brooding phenomenon and have declares this species to have a longer brooding time than any other known animal.
Egg brooding happens after the parent species lays the eggs. The parents then do everything in their power to protect those eggs so that offspring can develop. This includes cleaning the eggs and guarding them from predators, which evidently risks the parents' own ability to survive.
In May 2007, during a deep-sea survey, researchers from MBARI, led by Bruce Robison, discovered a female octopus (Graneledone boreopacifica), clinging to a rocky ledge just above the floor of the canyon, about 1,400 meters (4,600 feet) below the ocean surface.
Over the next four and one-half years, the researchers dove at this same site 18 times. Each time, they found the same octopus, which they could identify by her distinctive scars, in the same place. 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 skin became loose and pale.
The researchers never saw the female leave her eggs or eat anything.
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.
After counting the remnants of the egg capsules, the researchers estimated that the female octopus had been brooding about 160 eggs.
Because the young octopus spend so much time in their eggs, by the time they hatch they are fully capable of surviving on their own and hunting for small prey. In fact, the newborns of G. boreopacifica are larger and better developed than the hatchlings of any other octopus or squid.
Such long brooding times present an evolutionary challenge, especially for animals such as octopus, which do not live very long.
This research suggests that, in addition to setting records for the longest brooding time of any animal, Graneledone boreopacifica may be one of the longest lived cephalopods. Most shallow-water octopuses and squids live just a year or two.
Read more at the Monterey Bay Aquarium Research Institute.
Octopus image via Shutterstock.