This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: For dolphins, the ocean is a world of sound. Their whistles carry social information, helping them communicate and stay connected, while echolocation—rapid-fire clicks—functions like underwater sonar, helping them navigate their surroundings and detect potential prey.
But dolphins aren't the only noisemakers. Fish make sounds in the underwater soundscape, as do vessel traffic and other human activities. For dolphins and their prey, the sounds they make may be just as important as the sounds they hear.
By eavesdropping on these cetaceans, researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute have uncovered new clues about how dolphins navigate and use their underwater world—including evidence suggesting that dolphins themselves may be eavesdropping on their prey and that their prey may be eavesdropping on them. Using an autonomous wave glider equipped with an acoustic recorder, the team spent two months listening across the East Florida Shelf, capturing a rare glimpse into the acoustic lives of dolphins along Florida's Atlantic coast. The findings, published in the journal PeerJ, reveal distinct patterns in dolphin whistles and echolocation, suggesting dolphins may favor different habitats for socializing and hunting.
Over two months, the wave glider captured nearly 62 hours of underwater sound, with dolphins detected in more than 1,600 recordings. Researchers then compared dolphin whistles and echolocation with environmental conditions, including depth, temperature, salinity, currents, productivity and human-generated noise, revealing not just where dolphins were detected but what may have shaped their behavior. Findings reveal that whistle activity, which is primarily associated with social behavior, was more frequently detected in nearshore waters and was influenced by factors including location, water temperature, sound levels and chlorophyll-a concentration.
Two prominent areas of predicted whistle activity emerged near St. Augustine and Ponce Inlet, with additional areas near Melbourne Beach and north of Ponce Inlet, suggesting that portions of the nearshore environment may be particularly important for dolphin social activity. Echolocation told a different story—and offered perhaps the most intriguing clue of all.
The rapid-fire clicks were concentrated from Melbourne to Ponce Inlet and offshore toward Long John Reef, where sound-producing fish were also abundant. The overlap suggests dolphins may be using acoustic clues from their prey as they hunt, giving researchers a way to pinpoint potential feeding grounds without ever seeing a dolphin or its prey. "What we're seeing is a fascinating separation between the acoustic behaviors dolphins use for social life and those they use for finding food," said Greg O'Corry-Crowe, a co-author, research professor at FAU Harbor Branch and National Geographic Explorer.
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