The Knowledge

How dolphins communicate – new discoveries from a long‑term study in Sarasota, Florida

Published

3 weeks ago

April 13, 2026

The Conversation

Brookfield Zoo Chicago's Sarasota Dolphin Research Program — Bottlenose dolphins are social creatures that use whistles and clicks to communicate with each other. Brookfield Zoo Chicago’s Sarasota Dolphin Research Program, taken under NMFS MMPA Scientific Research Permit

Laela Sayigh, Woods Hole Oceanographic Institution

Human fascination with bottlenose dolphins goes back thousands of years, at least as early as Greek mythology.

But it wasn’t until the 1960s that methodical research into dolphin communication began. Scientists like John Lilly and the husband-and-wife team of Melba and David Caldwell tried various experiments to decipher the sounds dolphins can make.

The Caldwells figured out a way to record isolated animals in human care. They discovered that each individual dolphin communicated mostly with one unique whistle, which they called the “signature whistle.” Researchers now know that these whistles convey identities much like human names do. Dolphins use them to stay in touch with each other in their murky habitat, where vision is limited. It’s like announcing “I’m over here!” when someone can’t see you.

This discovery is foundational to my own research. I’ve been studying communication in wild dolphins since the mid-1980s, when I joined my mentor Peter Tyack in documenting signature whistles in wild dolphins for the first time. Our team’s research focused on a resident community of free-ranging bottlenose dolphins in waters near Sarasota, Florida, where I continue to work today.

This collaborative study, led by Randall Wells of Brookfield Zoo Chicago’s Sarasota Dolphin Research Program, involves numerous researchers from a variety of institutions, who study different aspects of dolphin biology, health, ecology and behavior. Begun in 1970, this is the longest-running research project on a population of wild cetaceans – whales, dolphins and porpoises – in the world.

one dolphin surfaces next to another's dorsal fin, which has a jagged edge at the top — Each dolphin has distinctive markings on its dorsal fin. Experienced researchers can sometimes identify them by sight in the field, and they photograph them to confirm their identity in the lab. Photo by Brookfield Zoo Chicago’s Sarasota Dolphin Research Program, taken under NMFS MMPA Scientific Research Permit

Recording and observing

Researchers know the age, sex and maternal relatedness of almost all of the approximately 170 dolphins in the Sarasota community. This depth of knowledge provides an unprecedented opportunity to study communication in a wild cetacean species.

The dolphins in the Sarasota project are periodically subject to brief catch-and-release health assessments, during which researchers, including me, briefly handle individual dolphins.

Our team attaches suction-cup hydrophones directly onto each dolphin’s melon – that is, its forehead. We then record the dolphins continuously throughout the health assessments, taking notes on who is being recorded when, and what is happening at the time.

This is how my colleagues and I were able to confirm that wild dolphins, like captive animals, produced large numbers of individually distinctive signature whistles when briefly isolated from other dolphins. Through observations and recordings of known free-swimming dolphins, we were further able to confirm that they produced these same signature whistles in undisturbed contexts.

We have organized these recordings into the Sarasota Dolphin Whistle Database, which now contains nearly 1,000 recording sessions of 324 individual dolphins. More than half of the dolphins in the database have been recorded more than once.

We identify each dolphin’s signature whistle based on its prevalence: In the catch-and-release context, about 85% of the whistles that dolphins produced are signature whistles. We can identify these visually, by viewing plots of frequency vs. time called spectrograms.

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file 20260306 57 g5fjiz.jpg?ixlib=rb 4.1 — Spectrograms of signature whistles of 269 individual bottlenose dolphins recorded in Sarasota. Figure created by Frants Jensen, with sound files from Laela Sayigh

Signature whistles and ‘motherese’

The Sarasota Dolphin Whistle Database has proved to be a rich resource for understanding dolphin communication. For instance, we have discovered that some calves develop signature whistles similar to those of their mothers, but many do not, raising questions about what factors influence signature whistle development.

We have also found that once developed, signature whistles are highly stable over an animal’s lifetime, especially for females. Males often form strong pair bonds with another adult male, and in some instances, their whistles become more similar to one another over time. We are still trying to understand when and why this occurs.

Dolphin mothers modify their signature whistles when communicating with their calves by increasing the maximum frequency, or pitch. This is similar to human caregivers using a higher-pitched voice when communicating with young children – a phenomenon known as “motherese.”

Slowed recording of a bottle-nosed dolphin without her calf, then with her calf. Courtesy of Laela Sayigh of Woods Hole Oceanographic Institution, and Brookfield Zoo Chicago’s Sarasota Dolphin Research Program. These sounds were obtained under a federal scientific research permit issued to R. Wells of SDRP.72 KB (download)

Also similar to humans is how dolphins will initiate contact with another dolphin by imitating their signature whistle – what we call a signature whistle copy. This is similar to how you would use someone’s name to call out to them.

Our team is interested in finding out if dolphins also copy whistles of others who aren’t present, potentially talking about them. We have seen evidence of this in our recordings of dolphins during health assessments, which provide a rare context to document this phenomenon convincingly. But we still have more work to do to confirm that these are more than chance similarities in whistles.

Shared whistle types

Another exciting development has been our recent discovery of shared whistle types — ones that are used by multiple animals and that are not signature whistles. We call these non-signature whistles.

I could hardly believe my ears when I first discovered a repeated, shared non-signature whistle type being produced by multiple dolphins in response to sounds we play back to them through an underwater speaker. We had previously believed that these non-signature whistles were somewhat random, but now I was hearing many different dolphins making a similar whistle type.

Our team originally had been using the playbacks to try to determine whether dolphins use “voice cues” to recognize each other – similar to how you can recognize the voice of someone you know. Although we found that dolphins did not use voice cues, our discovery of shared non-signature whistle types has led to an entirely new research direction.

A woman on a boat wearing headphones and looking at a laptop — The author listens to dolphin whistles on a boat in Sarasota. Jonathan Bird from the film ‘Call of the Dolphins’/Oceanic Research Group, Inc.

So far, I’ve identified at least 20 different shared non-signature whistle types, and I am continuing to build our catalog. We are hoping that artificial intelligence methods may help us categorize these whistle types in the future.

To understand how these shared non-signature whistle types function, we are carrying out more playback experiments, filming the dolphins’ responses with drones. We’ve found that one such whistle often leads the dolphins to swim away, suggesting a possible alarm-type function. We have also found that another type might be an expression of surprise, as we have seen animals produce it when they hear unexpected stimuli.

More difficult, more interesting

So far, the main takeaway from our experiments has been that dolphin communication is complex and that there are not going to be one-size-fits-all responses to any non-signature whistle type. This isn’t surprising, given that, like us, these animals have complicated social relationships that could affect how they respond to different sound types.

For instance, when you hear someone call your name, you may respond differently if you are with a group of people or alone, or if you recently had an argument with someone, or if you’re hungry and on your way to eat.

Our team has a lot more work ahead to sample as many dolphins in as many contexts as possible, such as different ages, sexes, group compositions and activities.

This makes my job more difficult – and far more interesting. I feel lucky every day I am able to spend working on the seemingly infinite number of fascinating research questions about dolphin communication that await answers.

This article has been corrected to better describe how dolphins respond to playback whistles.

Read more stories from The Conversation about Florida.

Laela Sayigh, Senior Research Specialist, Cetacean Communication, Woods Hole Oceanographic Institution

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Food and Beverage

Lifesum Survey: 90% Say Ultra-Processed Foods Are Engineered to Be Hard to Stop Eating

Published

2 days ago

May 2, 2026

Charles Elliot, Daily News Staff

A new nationally representative survey from health app Lifesum suggests Americans increasingly view ultra-processed foods (UPFs) as more than a “willpower” issue. The research, based on responses from 2,000 U.S. adults, found 90% believe UPFs are intentionally engineered to be hard to stop eating—while 81% say they’ve personally felt unable to stop once they start.

delicious junk food placed on table. Ultra-Processed Foods — Photo by ready made on Pexels.com

Ultra-Processed Foods Under Fire: New Data Shows Regret, Loss of Control, and Calls for Regulation

The survey also points to a widespread “control and regret” loop: 67% report they’ve tried and failed to cut back on certain ultra-processed foods, and 80% say they feel regret or frustration after eating them. The findings land as UPFs remain a dominant part of the American diet—federal dietary data indicates more than half of calories consumed in the U.S. come from ultra-processed foods, and high consumption has been linked in multiple studies to higher risks of obesity, type 2 diabetes, and cardiovascular disease.

Lifesum says the data reflects shifting public attitudes toward stronger oversight. In the survey, 81% support clearer warning labels on ultra-processed foods, 59% support restrictions on marketing, and 47% support regulation similar to tobacco or alcohol. The release also cites a recent report from researchers at Harvard University, the University of Michigan, and Duke University arguing that UPFs share similarities with cigarettes—such as engineered reward pathways and marketing designed to drive repeat consumption—strengthening the case for tighter regulation.

What to watch for

Labeling momentum: With 81% backing warning labels, expect more debate over front-of-package disclosures and clearer definitions of “ultra-processed.”
Marketing restrictions: The 59% support level signals potential policy focus on advertising practices—especially around kids and high-frequency digital targeting.
Regulation framing shift: The 47% support for tobacco-style rules suggests UPFs may increasingly be discussed as a public health and consumer protection issue, not just nutrition advice.
Scientific scrutiny vs. industry response: As more researchers compare UPFs to cigarettes, watch for counter-messaging from food manufacturers and lobbying around how UPFs are categorized.
Consumer behavior tools: Demand may grow for evidence-based guidance and tracking tools (apps, labeling systems, education campaigns) that help people reduce UPF intake without relying solely on self-control.

Source

Lifesum (official site)