Seals produce a remarkable range of sounds, from barks and grunts on land to eerie trills and roars underwater, and nearly every sound serves a specific social purpose. Across the 34 or so living pinniped species, researchers have documented vocalizations in air from at least 32 species and underwater calls from 22, spanning everything from simple broadband grunts to complex, repeating songs. These sounds help seals find mates, defend territories, identify their offspring in chaotic colonies, and even gauge the size of a rival. The story gets stranger from there: some seals learn to mimic human speech, others go deliberately silent to dodge predators, and populations separated by hundreds of miles develop what amount to regional accents.
The Range of Sounds Seals Make
If you’ve ever been near a seal haul-out, you’ve probably heard the loud, throaty barking and growling that carries across the beach. But that in-air noise is only part of the picture. Seals vocalize both on land and underwater, and the two repertoires can be strikingly different. On land, common sounds include barks, growls, snorts, and hisses. Underwater, the palette expands to include tonal calls, roars, trills, chirps, and even extended “songs” made up of repeating sequences. A study of male harbour seals in California identified five distinct underwater call types just in that one population: grunts, groans, creaks, bubbly growls, and roars.1Animal Behaviour. Underwater acoustic displays and individual variation in male harbour seals, Phoca vitulina Other species add their own specialties. Bearded seals produce long, descending trills that sound almost electronic. Leopard seals sing elaborate underwater songs. Elephant seals belt out deep, rhythmic pulses that carry across entire beaches.
The sheer diversity is worth pausing on. The sounds range from broadband grunts and roars to complex amplitude-modulated trills, chirps, repeated sequences, and full song. Context matters enormously: a sound that functions as a threat on a crowded beach may have no equivalent underwater, and vice versa. This is why researchers often study the same species twice, once in air and once below the surface, to understand the full vocal repertoire.
How Seals Produce Their Sounds
Seals make their in-air calls the same basic way you do: by pushing air across vibrating vocal folds in the larynx. This pneumatic mechanism is shared with most terrestrial mammals. But the details of the hardware vary quite a bit across species. In harbour seals and grey seals, the vocal folds sit perpendicular to the airflow, much like in a dog or a human. In elephant seals and sea lions, however, the vocal folds are rotated so the front attachment sits farther forward, positioning them near the belly side of the larynx. That rotated orientation resembles what’s seen in hippos and whales, and it may represent evolutionary convergence among mammals that vocalize underwater.2The FASEB Journal. Comparative Anatomy of the Larynx in Pinnipeds (Seal, Sea lion, Walrus)
Harbour seals also have a unique anatomical feature: forward-projecting “prong-shaped” structures at the opening of the larynx, supported by fibro-elastic cartilages. These prongs can bend forward to seal off the airway, which appears to be a reflex that protects against inhaling water or food. The muscle arrangement driving those prongs is unusual too. In most mammals, the muscle controlling vocal fold movement is a single unit, but in harbour seals it’s split into two parts: one that closes the vocal folds for sound production and another that flexes the prongs to shut the airway entrance.3Journal of Experimental Biology. Laryngeal and soft palate valving in the harbour seal (Phoca vitulina) This dual system lets harbour seals switch rapidly between vocalizing on land and diving in water without drowning themselves in the process.
What Mating and Territorial Calls Mean
For many seal species, underwater vocalizing ramps up dramatically during the breeding season, and males do most of the talking. In harbour seals, adult males produce elaborate underwater acoustic displays while females stay quiet, vocalizing only on land when threatening other seals. The males’ calls show significant individual differences, especially in roar frequency, which means each male’s display functions almost like a vocal fingerprint. Researchers have suggested these displays serve dual duty: deterring rival males and advertising to females.1Animal Behaviour. Underwater acoustic displays and individual variation in male harbour seals, Phoca vitulina
Northern elephant seals take this further. Males produce loud, rhythmic calls with a pulsing structure, and the physical properties of these calls are tied to body size. Larger males produce calls with more pulses and lower frequencies, so a rival can estimate a challenger’s size just from hearing the call. Interestingly, though, when researchers played back modified calls to breeding males, altering pulse rate, number of pulses, or frequency content, the males responded about equally to all versions. This suggests that elephant seals don’t simply assess a rival based on a single acoustic feature. Instead, they seem to learn and remember the specific calls of known competitors, then use those learned associations to decide whether to fight or back off.4PubMed Central. Rival assessment among northern elephant seals: evidence of associative learning during male–male contests The call itself isn’t a simple “I’m bigger than you” signal. It’s more like a name tag that other males learn to associate with past encounters.
Male bearded seals use a different strategy. During the Arctic breeding season, they produce long, haunting underwater trills that serve both to attract females and to compete with other males.5Polar Biology. Bearded seal (Erignathus barbatus) vocalizations across seasons and habitat types in Svalbard, Norway These calls can last over a minute each and carry considerable distances through cold polar water. The trills have a distinctive descending quality that, to a human listener, sounds almost like a science-fiction sound effect.
How Mothers and Pups Find Each Other
On a breeding beach packed with hundreds or thousands of seals, a mother returning from a foraging trip faces a genuine needle-in-a-haystack problem: she needs to find her own pup among a crowd of very similar-looking, very noisy youngsters. Voice recognition solves this. In harbour seals, mothers can distinguish their own pup’s calls from those of unrelated pups, responding more strongly and approaching more quickly when they hear the familiar voice.6Animal Behaviour. Mother–pup vocal recognition in harbour seals: influence of maternal behaviour, pup voice and habitat sound properties
This recognition runs in both directions. In Cape fur seals, which breed in extremely dense colonies, playback experiments have shown that pups can identify their own mother’s call and that mothers can pick out their pup’s voice, even when the calls of other individuals sound very similar acoustically. The mutual nature of the recognition is crucial: in a colony where thousands of animals are packed together and pups may wander, both parties need to be actively searching for each other’s voice.7PubMed. Mutual mother-pup vocal recognition in the highly colonial Cape fur seal: evidence of discrimination of calls with a high acoustic similarity These “pup-attraction calls” and “female-attraction calls” encode identity information that persists even amid the chaotic noise of a breeding colony. For the seals, it’s the acoustic equivalent of a mother calling her child’s name across a crowded playground.
Leopard Seal Songs
Leopard seals are apex predators in Antarctic waters, but during the breeding season, males reveal an unexpectedly artistic side. They spend hours underwater producing long, structured vocal performances: unique sequences of stereotyped call types arranged into what researchers call “songs.”8PubMed Central. Leopard seal song patterns have similar predictability to nursery rhymes Each male sings his own version, but the songs follow predictable patterns. A recent analysis found that the predictability of these call sequences is comparable to that of nursery rhymes, meaning the songs have a loose but real structure, not random and not rigidly fixed, sitting in a sweet spot that makes them memorable and recognizable.
Singing is physically demanding. Smaller male leopard seals appear to push harder early in the breeding season, producing more calls per bout than larger males. But as the season wears on, these smaller males tire out, needing more breaks and producing fewer calls per bout, while larger males maintain a steadier output throughout.9PubMed Central. Calling underwater is a costly signal: size-related differences in the call rates of Antarctic leopard seals This pattern suggests that sustained singing honestly signals a male’s stamina and body condition. A male who can keep up a consistent performance across weeks of breeding season is advertising his fitness in a way that’s hard to fake.
When Silence Is the Message
Not all seal communication involves making noise. For Weddell seals in the Antarctic, going quiet is itself a survival strategy. These seals breed on and under the stable “fast ice” that extends from the Antarctic coastline, and while they’re under that protective ice canopy, they vocalize freely, using loud calls to advertise and defend underwater mating territories. But when the fast ice breaks up and no longer shields them from predators like killer whales and leopard seals, Weddell seals go nearly silent. The hypothesis is straightforward: when you’ve lost your refuge, advertising your position with sound becomes too dangerous. Silence functions as an anti-predation strategy, and the shift from noisy to quiet tracks neatly with the seasonal breakup of their ice habitat.
This behavioral flexibility shows that seal vocalizations aren’t just reflexive outbursts. Seals modulate when and whether they call based on the perceived risk of being overheard by something that wants to eat them. It’s a reminder that every sound in the wild has a cost-benefit calculation behind it.
Vocal Learning and Talking Seals
One of the most surprising discoveries in pinniped research is that some seals can learn entirely new sounds, including imitating human speech. The most famous example is Hoover, a male harbour seal raised by a Maine fisherman in the 1970s before being transferred to the New England Aquarium. Hoover learned to produce phrases that sounded like a gruff New England accent, saying things that listeners interpreted as “hello there” and “get outta here.”10PubMed. Hoover the talking seal A detailed acoustic analysis confirmed that Hoover wasn’t just producing sounds that happened to overlap with speech. His vocalizations genuinely contained human speech cues, making him one of the very few mammals outside of humans demonstrated to engage in vocal learning.11Canadian Journal of Zoology. Vocalizations and vocal mimicry in captive harbor seals, Phoca vitulina
Vocal learning is the ability to hear a new sound and then modify your own vocal output to reproduce it. This is common in songbirds and parrots but extremely rare among mammals. Humans do it effortlessly, which is how we learn language, but most other mammals cannot. The fact that harbour seals share this capacity has made them a valuable model for studying the neurobiology of vocal learning. A related finding in another pinniped, a California sea lion named Ronan, showed that sea lions can synchronize head movements to a musical beat with a precision indistinguishable from that of adult humans.12Scientific Reports. Sensorimotor synchronization to rhythm in an experienced sea lion rivals that of humans Together, these findings challenge older ideas that beat perception and vocal flexibility are unique to humans or require specific brain structures found only in vocal-learning species like songbirds.
Regional Accents in Seal Calls
Seals from different geographic populations don’t all sound the same. When researchers compared underwater calls of male harbour seals from colonies in Norway, Sweden, and Scotland, they found differences in frequency contours and in which call types were used most often. These vocal differences likely reflect limited exchange of individuals between distant colonies, combined with strong site fidelity, meaning most seals return to the same breeding location year after year.13PubMed. Geographic variation and acoustic structure of the underwater vocalization of harbor seal (Phoca vitulina) in Norway, Sweden and Scotland
A broader analysis covering ten harbour seal sites across the species’ entire range confirmed that vocal variation exists at multiple scales: between ocean basins, between regions within a basin, between populations, and even between subpopulations at nearby sites. The researchers concluded that site-specific factors shape how vocal structure develops, providing evidence for what amount to vocal dialects.14The Journal of the Acoustical Society of America. Patterns in the vocalizations of male harbor seals Whether these dialects arise from genetic differences, cultural transmission between generations, or acoustic adaptation to local underwater environments (or some combination) remains an open question. But the pattern itself is consistent: if you moved between seal colonies, you’d hear differences analogous to regional accents in human speech.
How Noise Pollution Changes What Seals Say
Oceans and coastlines have gotten louder over the past century, with shipping traffic, sonar, construction, and other human-generated sounds filling the acoustic space that seals depend on. Seals are not passive victims of this change; they actively adjust their calls. When harbour seal pups were exposed to increasing levels of background noise, they lowered the pitch of their calls. Some pups also adjusted loudness and the distribution of energy across frequencies, changes consistent with what’s known as the Lombard effect, where a vocalizer raises or modifies its output in response to background noise.15PubMed Central. Vocal plasticity in harbour seal pups
The fact that even very young seals show this vocal plasticity is encouraging in one sense: seals aren’t stuck with a fixed call that gets drowned out. But there are limits to how far any animal can compensate. Lowering pitch or raising volume takes energy, and if noise levels are persistently high, the constant adjustment could affect energy budgets, especially in pups that are still growing. There’s also a recognition problem: if a mother is tuned to the normal pitch of her pup’s calls, a noise-forced shift in pitch could make reunification harder in the very conditions that already make communication more difficult. Researchers don’t yet know where the breaking point is, but the adjustments themselves show that anthropogenic noise is a real and measurable pressure on seal communication systems.
Hearing in Two Worlds
To understand what seal calls mean, it helps to know what seals can hear. Unlike purely marine mammals like dolphins, seals live in both air and water, and their hearing has evolved to function well in both environments. Spotted seals show underwater hearing sensitivity typical of a marine mammal, but their in-air hearing is comparable to that of fully terrestrial carnivores of similar size.16Journal of Experimental Biology. Amphibious hearing in spotted seals (Phoca largha): underwater audiograms, aerial audiograms and critical ratio measurements Ringed seals, an ice-dwelling Arctic species, show the same pattern: acute hearing both above and below the surface.17Journal of Experimental Biology. Amphibious hearing in ringed seals (Pusa hispida): underwater audiograms, aerial audiograms and critical ratio measurements
This dual-media hearing makes biological sense. A harbour seal needs to hear her pup calling on a beach, hear a rival male’s underwater roar while diving, and detect the approach of a predator in either environment. The fact that seals haven’t traded aerial hearing for underwater sensitivity (or vice versa) means that calls produced in air and calls produced underwater are both operating within a well-tuned sensory system. It also means that noise pollution in either medium, whether it’s a boat engine underwater or an aircraft passing overhead, has the potential to interfere with communication.
Listening for Seals to Protect Them
Because seals are vocal and their calls are species-specific, researchers have begun using passive acoustic monitoring to track populations without ever seeing the animals. Networks of underwater microphones can record continuously for months, and automated detection tools can scan those recordings for seal vocalizations. This approach is especially valuable for rare or elusive species. Work on the Mediterranean monk seal, one of the world’s most endangered marine mammals, has focused on developing automated detection frameworks to identify monk seal calls in large acoustic datasets, providing tools to assess habitat use and population presence in areas where visual surveys are impractical.18The Journal of the Acoustical Society of America. Building on the Mediterranean monk seal vocal repertoire: Foundations for long-term passive acoustic monitoring
Passive acoustic monitoring also has the advantage of being non-invasive. Traditional seal surveys often involve approaching animals closely enough to count or tag them, which causes disturbance. Listening from a distance lets researchers gather data on when seals are present, how actively they’re breeding (since vocal activity spikes during mating season), and whether particular habitats are being used, all without the animals ever knowing they’re being studied. As detection algorithms improve, this kind of eavesdropping is becoming a core tool in marine mammal conservation, turning the seals’ own voices into data points for their protection.