Researchers at the Konrad Lorenz Institute of Ethology of the University of Veterinary Medicine, Vienna, have discovered that zebrafish use social learning for assessing risk.
Individuals in some species learn information about food, predators, and potential mates indirectly from conspecifics, without taking unnecessary risks by learning directly for themselves (‘social learning’).
The researchers investigated whether zebrafish use social learning to assess risk – ‘boldness/shyness’ behavior.
They found that wild zebrafish, which are more timid than their domesticated counterparts, became emboldened after interacting with domesticated zebrafish.
The opposite did not occur, however. When the bolder domesticated zebrafish came in contact with wild zebrafish, they did not become more cautious.
To test fish disposition, the scientists scored ‘boldness’ as the response to a moving object. If fish approached the object relatively closely, they were classified as ‘bold’, while those who tended to stay at the back of the tank were considered ‘shy’. When the wild fish were allowed to interact with bolder domesticated fish, they became less likely to avoid the moving object.
These results, published the journal Animal Behaviour, confirm the researchers´ hypothesis that zebrafish use social learning for assessing risk: they observe other individuals’ behavior, and change their own behavior accordingly. The findings also indicate that zebrafish adapt their social-learning strategies to the costs of a perceived risk, as the domesticated bold fish did not change their behavior after interacting with the shy fish.
“When a zebrafish moves a few centimeters closer to an unfamiliar object than its buddies it may not seem like a big deal to human observers,” said lead author Dr Sarah Zala, “but 3 cm is about one ﬁsh length and in nature might mean exposing the fish to a predatory attack. So in reality, from the fish´s point of view, he is taking a big chance.”
The team also investigated whether zebrafish adapt their behavior to conform to the behavior of a larger group (‘social conformity’), but found no evidence for this hypothesis.
Future studies should be able to utilize this model species to incorporate genetic and genomic tools to study the development and evolution of social learning.
Bibliographic information: Zala SM, Määttänen I, Penn DJ. 2012. Different social-learning strategies in wild and domesticated zebrafish, Danio rerio. Animal Behaviour 83, 1519-1525; doi: 10.1016/ j.anbehav.2012.03.029