Scientists used a remotely operated vehicle to observe a patient deep sea octopus mum who tended her eggs for more than four years until they hatched.
The octopus protected and tended her eggs until they hatched 53 months later, according to a study in the journal PLOS ONE by Bruce Robison from Monterey Bay Aquarium Research Institute and colleagues.
Octopuses typically have a single reproductive period during their life, where the females protect and take care of their fertilised eggs until they hatch.
Shallow-water octopuses typically care for their eggs for one to three months but little is known about the brooding of deep-sea species.
Using a remotely operated vehicle to monitor the Monterey Submarine Canyon off central California, the scientists discovered a deep-sea octopus in 2007 on the sea floor about 1,400 metres deep.
When they returned in May 2007, the same octopus was sighted up on the rock and guarding a clutch of attached eggs.
The scientists returned to the site 18 times to monitor egg development and measure the length of her brooding period from its inception.
Each time the researchers returned, they found the same octopus clinging to the vertical rock face, arms covering her eggs. Continuous growth of the eggs led scientists to conclude that it was the same clutch throughout.
About 160 eggs hatched sometime between September and October 2011.
At 53 months, this is by far the longest egg-brooding period reported for any animal species.
Since these results are specific to the observation of one octopus brooding period, the authors suggest that these results may not be unique to all deep-sea species.
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