Hello and welcome to another Fun Fact From Flora ,
Today, because I need it, we are returning to the glorious, glowing marine realm and taking a look at the Hawaiian bobtail squid. Yes — it is totally as adorable as it sounds.
He’s SO SMOL . ** Look at him taking down this shrimp like a badass
Now, I"m not even squidding , these guys get even cooler. Because — like everything near and dear to me — they glow (apart from Clare — you need to work on that).
The reason that they do this is very cool, they hunt at night and therefore hunt at moonlight. But if they block out the very little light that there is when they are about to attack their prey, that is not very subtle, and so they glow to mimic the moonlight so that their prey cannot tell that they are there.
COOL, HUH?
But what is even cooler is that they harbour these little bioluminescent bacteria to do the glowing part for them. These guys are called Vibrio fischeri and they live inside a specialised organ.
But how do they get there?
Some animals that are super reliant on symbionts actually pass them down from parent to child. This is a way of making sure that your offspring have exactly what they need (I mean MY parents didn’t give me any bioluminescent symbionts, but whatever I"m not that bitter about it or anything).
This is especially important if you’re — I don’t know — an aphid and you eat something really dumb and nutritionally devoid like plant sap. You REALLYneed those bacteria to make your essential nutrients for you so you get them all the way from birth.
But this guy doesn’t do that. He’s born with 0 bacteria in his little light organ. So he has to do something pretty remarkable.
A baby bobtail squid hatches out and has to suss out getting some of these neat little bacteria in its light organ. These bacteria are present in the seawater at a concentration of about 100 per ml.
That might sound like quite a lot. But there are 1,000,000bacteria in every ml of seawater (enjoy thinking of that on your next holiday).
The odds aren’t so good.
But the squid does not give up.
When its born it encounters a couple of friendly bacteria in the first few seconds. It then uses these weird hairy arm-looking things to waft the bacteria into those pores at the bottom there (don’t worry — once the bacteria is established the weird hairy arms fall off although actually I don’t know if that makes things better or worse).
And once inside the squid has to make sure that only the lovely, glowing Vibrio fischeri are the ones that grow.
We really don’t understand this yet. We think it maybe kills some of the competing cells with its immune system, we think that maybe the squid feeds the bacteria with some yummy mucus but really we have no idea.
But almost every time, the squid is able to pick one bacteria, just ONE out of literally THOUSANDS , and encourage it to grow and colonise its light organ. There are NO OTHER SPECIES that grow inside these little organs. WoW.
SIDE NOTE I think this is hilarious. At dawn, when the squid stop hunting, they eject 95% of these bacteria. SPLOOP. Out you go.
And then they bury themselves in the sand to rest.
This is probably for two important reasons — to help control the bacterial population and CRUCIALLY to make sure that there are enough of the friendly glowing bacteria in the water for baby squid to find some when they hatch. Kind of like a daily top up of bacteria into the water to help out your mates
It’s such a weird and wonderful world out there.
Lots of love,
Flora xxx
Here’s your animal falling over:
