Dolphins and fishermen in Laguna, Brazil, enjoy the same food, plump silver mullets. But instead of competing with each other, they actually collaborate. But did you know that dolphins have been collaborating with humans since 1847?
Bottlenose dolphins actively herd fish towards local fishermen in Laguna, Brazil, and then signal with tail slaps for the fishermen to cast their nets. This collaboration has existed since at least 1847.
The Fishermen and Dolphin Collaboration
Dolphins will chase schools of mullets toward shore, where a row of fishermen will stand waist-deep in the water, nets in hand. The fishermen can’t see the fish because of the murky water, so they watch the dolphins instead.
When the dolphins slap their heads or tails against the water, it signals the fishermen to cast their nets, which breaks up the schools and makes individual fish easier to catch.
Since the 1980s, scientists have been aware of this mutually beneficial relationship. They’ve also noticed that in this population of about 60 dolphins, only a few of which cooperate with fishermen, the helpers tend to congregate with other helpers.
But Mauricio Cantor, a biologist at the Brazil’s Federal University of Santa Catarina, and his colleagues were perplexed. According to his research, the fishermen-helping dolphins form strong social bonds with one another. (Source: National Geographic)
Friends Stick Together
Cantor and colleagues conducted the study by cruising around the coastal lagoons of southern Brazil, photographing the dolphins they encountered to identify individuals.
They compiled hundreds of records detailing which dolphins were interacting with one another and what they were doing together. They also used a non-invasive technique to collect genetic samples, which allowed them to determine how and if the animals were related.
The findings, which were published in the journal Biology Letters on April 9, revealed that the helper dolphins actively choose to spend time with one another. It is less important whether individuals are related or members of the same age group or sex; the strongest social ties form among dolphins who use the same fishing technique.
They prefer to be with each other, and not just when they’re cooperating with fishermen,Mauricio Cantor, Biologist at Brazil’s Federal University of Santa Catarina
These helper dolphins, for example, would travel together, roll around with each other, and even nap side by side. (Source: National Geographic)
Learning from Colleagues
According to Janet Mann, a dolphin expert at Georgetown University in Washington DC, the new study reveals a cultural phenomenon.
Anthropologists and psychologists agree on two basic criteria: that the behavior is socially learned and that the behavior distinguishes between groups.Janet Mann, Dolphin Expert, Georgetown University
Mann is researching a bottlenose dolphin population in Shark Bay, Australia. Some animals have begun to carry protective sea sponges on their beaks as they scour the seafloor for prey. Daughters learn it from their mothers, and spongers form cliques with other spongers, making it a cultural tradition, according to her research. Similarly, the new study finds that helper dolphins in Brazil prefer socializing with other helpers. It’s unclear whether the cooperative dolphins learn from their peers, but Cantor believes they do. (Source: National Geographic)
Image from Earthtimes