Off the coast of Laguna Municipality, in southwestern Brazil, for at least a hundred years a strange cooperation has been occurring: two different species of predators cooperating and synchronizing. The objective of this strategy is for the human and the bottlenose dolphin to obtain, together, more booty than each individual obtains. And they succeed, according to a study that analyzed this behavior. In the inner lake that forms along Brazil’s Atlantic coast, the area’s artisanal fishermen know that they must cast their nets at intervals of no more than 20 seconds when wild dolphins dive into the water after emitting their distinctive clicks. This aquatic “grazing” serves a classic purpose of military strategy: When a school of fish splits up to try to avoid danger, they fall into each other’s clutches, and vice versa.
“The school of fish, coordinated and in a group, is unreachable,” said Mauricio Cantor, lead author of a new study from the University of Oregon in the United States. With practice, this “co-learning,” as biologists call it, has allowed both groups to understand that if dolphins beach fish and fishermen cast their nets, practically one With both hunters, then the catch will be higher. It is a balance between local subsistence fishermen and 50-60 dolphins that has remained stable for at least 100+ years on record. The work to document it has taken nearly two decades and the journal details today’s event PNAS,
Scientists have observed that “dolphins dive longer and change their behavior” when they feed with fishermen. And, above all, dolphins who cooperate with humans increase their chances of survival by 13%, “a sign of long-term benefit”, as they reduce the risk of accidentally dying in the nets of large vessels when out to sea for food. Let’s reduce “Elderly fishermen name them, they can recognize them, and allies adore them nice dolphin”, jokes the researcher.
Cantor highlights the synchronization dynamics between the two species while hunting. In evolutionary terms, these cooperative practices are “a rare phenomenon”, ecologists also point out. Another case of cooperation between humans and birds is known in Africa to obtain honey, which would be their next area of work. As this is such a rare occurrence, the authors devote the last section of their publication to presenting possible conservation scenarios where traditional fishing practices could continue with stable populations of dolphins in balance with their environment.
Dolphins dive longer and change their behavior, cooperatives live longer, a long-term display of benefits
Mauricio Cantor, University of Oregon researcher
It is this cooperation between the species that has led the researcher’s team to develop a complete multiplatform system to record what happens on the beach of the lake. The study measured the phenomenon by land, sea and air: aerial drone images, scientists taking data on the ground, underwater headphones to detect dolphins’ echolocation clicks and the noise of submerged nets. Objective: To record in detail how the two species have learned to coexist and interact for the same prize without destroying each other.
Cultural transmission among dolphins sets Adrián González, head of marine mammal keepers at the Oceanographic de Valencia and who was not involved in the research, what sets this study apart from others because of how well-documented it is. “There is learning from parents to children, which means that the culture benefits the dolphins in the long term”, the experts detail, and emphasises: “The work highlights that the specimens that survive the most are, in this case fish, and the less energy waste they feel”. Regarding conservationism in the area, researcher Gonzalez suggests that the local population of the lagoon probably has a lot to do with the peaceful co-ordination between the two predatory species, as Brazil is not much of a whaling country, thus facilitating more fluid cooperation. . ,
José Zamorano-Abramson, from the Evolutionary Psychology Group at the University of Complutense, considers that the “synchronized cooperation strategy” is a “great contribution of the work”, because “it shows synchrony between different species to achieve an external objective”. , The professor, who was not involved in the study, reports that since the time of the naturalist Pliny the Elder, more than 2,000 years ago, there have been reports of fishermen along the Mediterranean coast using cetaceans to catch fish. The researchers explain how, today, encounters between people and bottlenose dolphins also occur in Australia and India, as in Brazil “but it also happened with orcas, like in Chile, where they were a big help in catching whales,” researchers say. Researcher, psychologist, who defines it as cooperative hunting.
Professor Zamorano-Abramson calls the new study one of the “few examples” where “social learning over time between species, a shared culture” has been measured. This is why the researcher in agreement with the authors highlights the importance of keeping this practice alive for the benefit of all.
The lead researcher admits a “bitter feeling” in his experience of studying the final stages of a unique collaboration in history, perhaps doomed to extinction due to the threat of intensive fishing that captures the dolphins that colonize the lagoon. leaves towards the high seas. the Atlantic. That’s why Cantor stresses that field studies are needed to “safeguard one of the last cases of cooperation between humans and wildlife”.
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