Says it's for their own protection.
It all started in April 2007 when a remotely operated vehicle descended 1,400 metres (4,600 ft) to a bunch of rocks sticking out of the ocean floor off the coast of California.
Video: MBARI
An octopus called Graneledone boreopacifica was spotted clinging to the rock. This is not at all surprising as it's quite a common species down there. This particular individual was a female brooding about 160 eggs, defending them from predators and ensuring they're kept clean and well-oxygenated. This again is not astonishing as such scenes have been witnessed many times before.
The surprise came months and years later... she was STILL at it!
Image: Robison et al |
Scientists returned to the spot 18 times over the next 4 and a half years, and recognised their subject by a small scar in one of her armpits. They watched as the youngsters developed and their little eyes became visible through the eggs. Conversely, they also watched as their mother wasted away, her eyes clouding over as she became increasingly pale and wrinkled.
Image: Robison et al Empty eggs |
Egg-brooding is a lot of effort, but it really works. We saw recently that at least two species of deep sea squid also get in on the act and carry their eggs around in their tentacles rather than attach them to a rock and swim away like shallow water squid. A good, long brooding period protects the eggs from harm and allows the youngsters time to develop and emerge with all the strength they need to tackle prey and escape predators at an early age.
With regard to our octopus, two questions arise.
Image: Robison et al |
It's possible that she withheld a few eggs within her body so she could reabsorb them for nourishment later. She may also feed on any eggs that become diseased or otherwise won't develop. Or maybe she just starves herself the entire time!
Secondly, there's the question of her lifespan. Most octopods spend an entire quarter of their lives sitting on their eggs and only live for a year or two in total. G. boreopacifica spends more time brooding than shallow-water octopods spend alive! If those 4 years looking after her eggs represent about a quarter of her lifespan, she may be among the most long-lived of any cephalopod!
.....
Check out the paper by Robison et al. on PLOS one.
incredible maternal instinct.
ReplyDeleteMother of the decade award right here.
ReplyDeleteCan you really live for four years without food, though? Octopods are usually such squishy and short lived creatures.
@TexWisGirl: Yup, amazing!
ReplyDelete@Esther: Four years does seem incredibly long! But who knows what adaptation they've had to undergo to live down there?
Four years is REALLY long, though, haha!
Fascinating story! The stuff from which legends are born.
ReplyDeleteYeah, you could make a really cool fable out of it!
ReplyDeleteThat's pretty amazing
ReplyDeleteAre we 100 percent certain though these weren't each a different clutch of eggs, and they just happened to find her with each one? Or perhaps this octopus spends most of its time brooding, and does it multiple times.. I guess that's a stretch but so is fasting for 4 years
I think they're quite sure it was the same eggs. They checked up on them often and they could see them developing over time.
ReplyDeleteThey can't be completely sure she didn't eat something at some point, but she was uninterested in food whenever they saw her.
Certainly there's opportunity for more research!