It’s a box with four corners and 24 eyes. Not the type you would want to pack a present in because the eyes on this box are found in the ocean, on the deadly box jellyfish.
Everything about box jellies are unexpected, they have gadget-like extendable arms, fish for prey, fire venomous harpoons and are mostly water yet they’re the deadliest animals on earth.
But here’s something else extraordinary about these animals that few people know…..they have a whole bunch of eyes, 24 in fact! In the Irukandji box jellyfish the eyes are found in clusters on the bottom of their box-like body, between its dangerous tentacles.
Now this is where it can get a bit tricky, so hang in there. Within each of the four clusters (one cluster for each side of the jelly) there are a total 6 eyes, made up of 3 different types of eyes. You still with us?
The first four eyes are slit and cup eyes, which are light sensitive. The other two are more complex eyes. They have a lens, retina and pupils. Like our eyes the pupils reacts to light intensity, i.e. in bright light it closes and in low light it opens up, which gives them depth of field so they can see things in 3-dimensions. They can tell how close objects or other animals are away, helping them when they’re fishing and luring prey.
All of the eyes are also facing inwards so the animal can look through itself (as it’s transparent), but more importantly it means they have 360 degree vision, which is impressive for a blob of water!
So as you can see (get what we just did there??) there is a lot going on within the eye clusters including last but not least, a balance organ called a ‘statocyst’ which jellyfish use to tell it which way is up. Which is kind of helpful as you don’t want to be head-butt a rocky reef and have your soft body shredded to pieces.
