Captive Dolphins Are Most Vocal During Play and Feeding — and It’s Not Just for Socializing
Underwater, a dolphin’s day unfolds through feeding, training, and bursts of play — and now, scientists have discovered that those shifts leave a clear signature in sound. According to a new study in PLOS One, bottlenose dolphins grow more vocal during structured activities, with play producing the strongest increase in pulsed sounds. The pattern ties changes in dolphin voices directly to engagement during enrichment.
“Our findings show that dolphins tend to ‘speak’ much more during structured moments like training, feeding, or play, revealing how closely their vocal activity reflects their social and emotional engagement,” the authors said in a press release.
How Dolphins Use Sound to Navigate and Socialize
Dolphins rely on a suite of sound types that serve distinct purposes in their daily lives. They use rapid clicks primarily for echolocation, while whistles and burst-pulsed sounds play key roles in social communication, coordination, and close-range interaction. Past research shows that dolphins actively shift between these sound types depending on what they are doing — hunting, traveling, socializing, or responding to one another — underscoring how tightly vocal behavior is linked to real-time context and behavior, according to Acta Astronautica.
Research also shows that dolphins alternate between passive “eavesdropping” on surrounding sounds and active echolocation when they need precise information, allowing them to gather cues quietly before switching to direct signaling.
In human care, captive dolphins rely on enrichment activities such as training sessions, feeding routines, and play interactions to stay physically active and mentally stimulated. Yet welfare assessments still depend largely on visible behavior.
Read More: Just How Intelligent Are Dolphins?
Tracking Dolphin Sounds During Training and Play
To capture how dolphin sound shifts across the rhythms of a typical day, researchers recorded 24 straight hours of continuous audio from seven bottlenose dolphins — two males and five females — living at Oltremare Marine Park in 2021. The recordings spanned everything from quiet, unstructured periods to feeding sessions, trainer-led exercises, and free play.
From that single day of sound, the team manually catalogued more than 3,000 whistles, saving each as an individual audio file, and used automated tools to detect over 1,200 pulsed vocalizations, including echolocation clicks, burst-pulse sounds, and the rapid buzzes dolphins produce while feeding. Together, the dataset captured the full range of how dolphins “sound” as they move through different physical and social settings.
When the researchers compared structured activity periods with quieter, unstructured time, a clear pattern emerged: dolphins became more vocal across every type of sound they produced. Whistles grew more frequent, pulses became denser, and overall calling activity surged during training, feeding, and play.
One activity stood out in particular. Play sessions triggered the highest rate of pulsed vocalizations, even more than feeding or training. Because pulsed sounds are often tied to close social interaction, coordination, and high-energy exchanges, the result suggests that play may be one of the most socially and cognitively stimulating parts of a captive dolphin’s day.
Using Sound to Improve Dolphin Welfare
“Understanding the relationship between vocalization patterns and activity types has direct implications for dolphin welfare. Our study can improve the design of enrichment programs to ensure that dolphins in human care maintain a healthy and dynamic acoustic repertoire,” the authors said in the press release.
The results suggest that changes in vocal frequency and duration could become practical tools for evaluating which enrichment activities truly engage dolphins.
Read More: How Eavesdropping on Clicks and Squeaks Helps Monitor Endangered Dolphins
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