Researchers diving deep in the Pacific Ocean to study a stretch of volcanic seafloor found something they never expected to see there: a massive group of octopus moms tending to their eggs, reports Science Magazine.
The baffling sighting confounded the geochemists, who took a detour from their original project to investigate why the octopuses were brooding eggs in a place where they were “unlikely to survive.”
The team stumbled upon the large cluster of purple octopuses, numbering several hundred of individuals, completely by chance, LiveScience notes. The researchers were exploring the Dorado Outcrop, a rocky patch of hardened lava stemmed from an underwater volcano, which lies about 155 miles west of Costa Rica.
Their initial goal was to gather samples of the warm fluids that ooze from cracks in the volcanic rocks, but one dive led to this serendipitous encounter and everything took a whole different turn.
The octopuses were discovered at a depth of 9,842 feet, tucked away inside the folds of the volcanic rocks. Over the course of multiple dives, the team spotted as many as 100 octopuses at a time.
These unexpected creatures, found protecting broods of eggs fixed onto the rocky outcrop, had a bizarre look; they sported enormous eyes that eclipsed their dinner-plate-sized bodies.
It was later established that they belong to an unknown species of the genus Muusoctopus, the team shows in a study detailing their observations, which spanned over two deep-sea expeditions conducted in 2013 and 2014.
The paper, published last month in the journal Deep Sea Research Part I: Oceanographic Research Papers, revealed a surprise twist: the octopuses were miraculously alive (and breeding!) in an area that essentially doomed them to an untimely demise.
“When I first saw the photos, I was like, ‘No, they shouldn’t be there! Not that deep and not that many of them,'” said study co-author Janet Voight, an associate curator of zoology at the Field Museum of Natural History in Chicago.
Deep-sea octopuses normally thrive in cold waters and would have trouble breathing in warm areas such as Dorado Outcrop, notes the National Science Foundation (NSF), which funded the research. To station a nursery in such a hostile environment equals “suicide,” state the researchers.
Trying to understand what drove these creatures to amass and spawn in such threating conditions that would inevitably provide their offspring little chance of survival, the team wondered if this was simply a case of reckless breeding behavior, or there was something else afoot.
Judging by the massive number of octopus moms hanging on to their patch of rock (despite showing signs of severe stress), Voight speculates that there could be an even larger group somewhere in the area.
According to her theory, that unseen group probably occupied all the prime breeding spots, leaving the rest to scramble for a patch of heated rock.
“Odds are that this outcrop has hollow areas where other females nurture their eggs to hatching,” Voight hypothesized.
“They’re analogous to boomers who have all the good jobs, while the millennials wait, seeking one little piece of cool rock,” she added.