Scientists Discover Box Jellyfish Can Learn and Adapt
In a surprising discovery, researchers have found that box jellyfish, known for their complex visual system and brainless nature, have the ability to learn. The findings, published in the journal Current Biology, shed light on the evolution of learning and could have broader implications for our understanding of cognition.
Box jellyfish, specifically the Tripedalia cystophora species, were chosen for the study due to their habitat in the sunlit waters of Caribbean mangrove forests. Researchers focused on the creatures’ swift about-face maneuver, which they execute when approaching a mangrove root. The roots rise through the water like black towers, while the surrounding water appears pale in comparison. However, silt can cloud the water, making it difficult for box jellies to determine the distance to the root.
To test their ability to learn, scientists created buckets with alternating dark and light stripes representing the mangrove roots and water, respectively. Box jellies were initially observed running into the bucket walls when the contrast between the stripes was lower. However, after a few collisions, the jellies adapted and began swimming further from the pattern on the walls, performing the about-face maneuver more frequently.
Further experiments involved removing visual neurons from the box jellyfish and observing their behavior in a dish. The cells were shown striped images while receiving a small electrical pulse to simulate collision. Within minutes, the cells started sending signals that would cause a whole box jellyfish to turn around. The speed at which they learned was described as “amazing” by the researchers.
Experts not involved in the study have hailed the results as a significant step forward in understanding the origins of learning. Associative learning, where an organism connects two stimuli or events, has only been convincingly demonstrated in cnidarians, a group that includes sea anemones, hydras, and jellyfish.
In future research, scientists hope to identify the specific cells responsible for the box jellyfish’s ability to learn from experience. They also aim to investigate the molecular changes that occur in these cells as the animals incorporate new information into their behavior. This could shed further light on the universality of learning among nerve cells and its role in the tree of life.
The discovery of learning abilities in box jellyfish highlights the complexity of their neural networks and raises questions about the evolution of cognition. Understanding these primitive animals’ cognitive abilities could provide valuable insights into the development of learning in different species, including humans.