As highly social beings, humans need good friends. When we surround ourselves with people who make us feel heard, safe and loved, our happiness increases , and according to numerous studies , it seems that we also live longer.
At the same time, as humans, believing ourselves to be extraordinarily complex beings, we tend to underestimate the importance of friendship in animals that seem simpler to us, and we ignore the relevance for them to surround themselves with friends to survive.
A group of researchers from Nova Southeastern University (NSU) has published a study in the journal Communications Biology focused on the value of friendship in fish . Specifically, they have worked with the green damsel or green castanet ( Chromis viridis ), a highly social pomacentrid species that can be found in shallow marine waters of coastal areas sheltered by reef lagoons and protected in corals of the Acropora genus. They usually swim in places like the Red Sea, the Line Islands, the Tuamotu, the Ryukyu Islands and New Caledonia.
During the investigation, the team compared the reactions of two schools of fish to the presence of a threat, which simulated a potential predator approaching. In one group they were surrounded by acquaintances or “friends”, and in the other by strangers or “strangers” of the same species.
The results were promising. According to the lead author of the article, Lauren Nadler, PhD student and assistant professor at NSU, the presence of “strangers” seemed to distract the fish, causing them to react later to threats and thus increasing the chances of becoming fish. at the predator dinner.
Scientists believe that this event is closely related to trust. When an individual in the school feels threatened by danger and reacts, neighboring fish have very little time to decide what to do. They have two options: they can trust that the danger is real and escape, or ignore the partner’s reaction. According to the NSU study, fish surrounded by acquaintances tend to rely much more on the movements of their neighbors, causing a chain escape. For this reason, schools of fish with a high degree of familiarity escape in a fast, agile and coordinated way before the attack of the predator. In summary, it could be said that trust in the group increases individual fitness, that is, the biological efficacy or number of descendants that each of them may have.
Study co-author Mark I. McCormick concludes: “Friendly relationships are important, both for humans and for less evolved taxa, such as fish. The more you trust your friends, the easier and more satisfying your life will be, both in and out of the water ”.
References:
Nadler, L. E., McCormick, M. I., Johansen, J. L., & Domenici, P. (2021). Social familiarity improves fast-start escape performance in schooling fish. Communications Biology, 4(1). https://doi.org/10.1038/s42003-021-02407-4
