---
title: "Box jellyfish · Animals and other organisms · Entities · Simulation Hypothesis"
url: https://simulation-hypothesis.com/entities/jellyfish
description: "A box jellyfish has no central brain, yet it showed associative learning."
license: https://creativecommons.org/licenses/by/4.0/
credit: "Ross Allan Dahl, Simulation Hypothesis (simulation-hypothesis.com)"
---

[Entities](https://simulation-hypothesis.com/entities) › Animals and other organisms › Nerve nets, no brain

# Box jellyfish

Tripedalia cystophora

A box jellyfish has no central brain, yet it showed associative learning.

Neurons

No published count

## Evidence

* It showed associative learning (a visual cue paired with a mechanosensory cue). The learning happens in the rhopalial nervous system, even though the animal has no centralised brain.  
Bielecki J, Dam Nielsen SK, Nachman G, Garm A (2023) Associative learning in the box jellyfish Tripedalia cystophora. Curr Biol 33(19):4150-4159.e5\. doi:10.1016/j.cub.2023.08.056.

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