Unveiling the science behind how "Octomums" use deep-sea thermal pools for egg brooding

The octo-mums gathered in Davidson Seamount, an underwater mountain to give birth to young ones. (Image: Associated Press)

A groundbreaking discovery off the coast of the Pacific Ocean reveals how mother octopuses use deep-sea thermal pools to brood their eggs. Thousands of female Muusoctopus robustus were observed nesting on the Davidson Seamount near hydrothermal vents.

These “octomums” lay upside down in dense, orderly rows within warm “hot tubs”, which accelerate embryo development, reducing brooding periods from decades to under two years.

The Science of Thermal Brooding

Octopuses are generally solitary and brood eggs slowly in the cold deep sea. The hydrothermal vents emit warm water, creating a microenvironment that elevates temperatures around the eggs.

This thermal boost increases metabolic rates in embryos, allowing them to grow faster and reducing their vulnerability to predation and environmental stress. Without these warm pools, the eggs might take five to eight years to develop fully.

Uncovering Maternal Strategies

The discovery was made during a 2018 expedition by the Monterey Bay Aquarium Research Institute with a remotely operated vehicle (ROV). Researchers documented the dense congregations of brooding mothers and collected crucial data on temperature, egg development and maternal behaviour. This research provided unprecedented visual evidence of this deep-sea parenting strategy.

Evolutionary Advantage in the Deep Sea

This behaviour highlights an extraordinary evolutionary adaptation. Hydrothermal vent sites are often opted by mother octopuses to ensure that their offspring develop faster in an otherwise inhospitable environment.

This study underscores the intricate link between environmental conditions and reproductive strategies. The study also reveals how deep-sea species exploit thermal advantages to maximise survival.