Brainless Box Jellyfish Learn How To Behave

 

Box jellyfish are learners, not thinkers, according to a recent study conducted by a team of German and Danish scientists.

We know that box jellyfish are brainless and rely on a nervous system developed over millions of years to navigate and hunt their prey.

It's a fact that box jellyfish have some kind of short-term memory, though it's unclear how long this learned behaviour lasts.

In this case, a Caribbean species of box jellyfish, tripedalia cystophora which is also found in South-East Asia, was studied resulting in clear evidence they can learn to manoeuvre around obstacles to avoid a potentially damaging collision.

The roots of mangrove trees, which form the breeding ground for box jellyfish, get in the way of catching small fish and prawns, and can snag fragile tentacles. So, these box jellyfish use their visual senses - their 24 eyes - to swim around the roots.   

If the same exists in other box jellyfish including the lethal chironex species, and it is understood that it does, then it could possibly explain why the number of people - with legs resembling mangrove roots - that are stung is relatively low.

All human stings are an accident, not an attack. 

Wrong place, wrong time, wrong animal. 

They most often occur on a sandy beach where the box jellyfish sit on the seabed, spread their tentacles and wait for an unsuspecting victim to swim into their trap.

Human activity - the sight of legs running and splashing nearby through the water - would visually disturb the box jellyfish who would attempt to move away and do their fishing elsewhere.

In their haste, people - particularly fast moving children - get in the way and this is where the majority of stings occur.

Following is further reading including the original study, media articles on the subject and a relevant post from this blog:

• Associative Learning In The Box Jellyfish
• New York Times Article
• Australian Geographic Article
• Why Is A Box Jellyfish So Deadly?