But these gelatinous, fingernail-sized creatures are capable of learning from visual cues to avoid swimming into obstacles - a cognitive ability never before seen in animals with such a primitive nervous system, researchers said.
These scenarios throw up plenty of dangers that could damage the jellyfish's fragile gelatinous membrane which envelops its bell-shaped body. This means they can be trained to"predict a future problem and try to avoid it", said Anders Garm, a marine biologist at the University of Copenhagen and the study's lead author.
If the bars were made more prominent, the jellyfish never hit the walls, remaining safely in the centre of the tank.If the stripes were removed entirely, the jellyfish constantly ran into the walls of the tank.The jellyfish learned their lesson in between three to six tries,"which is basically the same amount of trials for what we would normally consider an advanced animal, like a fruit fly, a crab or even a mouse," he said.