Most of the barking you hear from “seals” on a pier or beach actually comes from sea lions and fur seals. Much of it is males telling other males to keep their distance. Mixed in is a softer chorus of mothers and pups calling to find each other in the crowd.1Animal Behaviour. Vocal recognition of mothers by Australian sea lion pups: individual signature and environmental constraints Barking is only one corner of seal communication, though, because many other seals do their talking underwater, out of human earshot.2Wikipedia. Pinniped
How to Tell a Barking Sea Lion From a True Seal
Biologists sort seals into two families. Eared seals include sea lions and fur seals. True seals, sometimes called earless seals, include harbor and gray seals. Walruses form a third, separate group. The families court differently: eared seals do their noisy courting mainly on land, while true seals and walruses court mostly at sea.3Springer Link. Pinniped Sounds That’s why the animals barking in plain view on rocks and docks are usually sea lions or fur seals. The barks of California sea lions are among the most famous seal sounds, while walruses make gong-like calls and Weddell seals sing complex songs.4Wikipedia. Pinniped
A few quick checks help. Sea lions and fur seals have small external ear flaps, while true seals have only a small hole on each side of the head. The flap is tiny and easy to miss from a boat or a pier, so it works best as a confirming detail. Movement and posture are easier to spot from far away. Sea lions and fur seals can turn their back flippers forward under the body, which lets them walk and even climb on rocks and docks. True seals can’t, so on land they hump and wriggle along on their bellies. A seal propped up on its front flippers with its chest lifted is likely a sea lion or fur seal, while one lying flat is more likely a true seal, though resting sea lions also lie flat.
Behavior adds another clue. Sea lions often lie in noisy, crowded piles, while harbor seals spread out and stay quiet. Individual animals can be hidden, asleep, or in odd positions, so ears, movement, posture, and behavior together are more reliable than any single one.
Barking to Claim Territory and Rank
Among male California sea lions, barking by bigger males limits where smaller males move and quiets their barking.5PubMed. Barking, dominance, and territoriality in male sea lions Males aim most of their barking and aggression at rivals closest to their own size.6PubMed. Barking, dominance, and territoriality in male sea lions Even young males around six years old who are seeking a territory use the same aggressive tactics as breeding adults.7PubMed. Barking, dominance, and territoriality in male sea lions
A standoff is easy to recognize. Two rival males meet chest to chest with heads raised, barking at each other at close range. Many of these encounters end when one male backs off or turns away after the exchange, with no contact at all. If neither yields, the encounter can escalate to lunging and biting, which is the outcome the barking usually helps avoid. A territory holder tends to patrol the edge of his patch of rock or beach.
Fights risk injuries that can end a breeding season, while a loud, steady bark advertises size and stamina, because holding a territory means constant calling, which is tiring.
Territory holders do the most barking. In Galápagos sea lions, males holding a territory call more often than males without one.8Wiley Online Library (Ethology). Seasonal Changes of Vocal Rates and Their Relation to Territorial Status in Male Galápagos Sea Lions (<i>Zalophus wollebaeki</i>) They call most at the start of holding a territory, when they mostly direct calls at other males.9Wiley Online Library (Ethology). Seasonal Changes of Vocal Rates and Their Relation to Territorial Status in Male Galápagos Sea Lions (<i>Zalophus wollebaeki</i>) But territorial males also aim calls at females, and call more when more females are in their area.10Wiley Online Library (Ethology). Seasonal Changes of Vocal Rates and Their Relation to Territorial Status in Male Galápagos Sea Lions (<i>Zalophus wollebaeki</i>)
The season matters too. In two captive male Australian fur seals, barking was highest from August to October, the breeding period in that region.11Australian Mammalogy. Faecal testosterone concentrations and the acoustic behaviour of two captive male Australian fur seals Their testosterone peaked in September, matching the busiest barking.12Australian Mammalogy. Faecal testosterone concentrations and the acoustic behaviour of two captive male Australian fur seals
Every Bark Carries a Voice Signature
Male Australian sea lion barks differ enough that a computer could match calls to the right male a little over half the time.13PubMed. Vocal identity and species recognition in male Australian sea lions, Neophoca cinerea Voices matter even more for mothers and pups. Sea lion mothers leave pups on the beach for days while they feed at sea. On return, each must find one pup among many, and both mother and pup call during reunions.14Animal Behaviour. Individual identity encoding and environmental constraints in vocal recognition of pups by Australian sea lion mothers Pups respond strongly to their own mother’s call and mostly ignore other females.15Animal Behaviour. Vocal recognition of mothers by Australian sea lion pups: individual signature and environmental constraints They recognize the rises and falls in loudness and pitch of her call; remove those, and pups barely react.16Animal Behaviour. Vocal recognition of mothers by Australian sea lion pups: individual signature and environmental constraints Mothers, for their part, use timing, loudness, and pitch together to recognize their pup.17Animal Behaviour. Individual identity encoding and environmental constraints in vocal recognition of pups by Australian sea lion mothers The two test each other’s voices first, before they get close enough to use smell or sight.18PubMed. Mother-pup recognition mechanisms in Australia sea lion (Neophoca cinerea) using uni- and multi-modal approaches
From the shore, a reunion has a pattern. A female lands and calls repeatedly while moving through the colony. Her pup answers with a higher-pitched, bleating call, and the pair keep calling back and forth as they close in. Once they’re near, they sniff to confirm they have the right partner. A pup that approaches the wrong female is often pushed away, which shows how much the match matters.
That’s also why a calling pup isn’t necessarily abandoned. A lone pup is often just waiting for its mother, who may be feeding at sea. Mothers can be gone for a day or more, so a pup left alone for hours is normal. Moving, touching, or handling it can break the reunion, because the mother may not find it where she left it or may reject it if the scent changes.
What True Seals Do Instead of Barking
Making sound underwater is physically different from making it in air, and sound travels differently in water.19Marine Mammal Acoustics in a Noisy Ocean. Pinniped Sounds Underwater calls therefore work differently from barks on land. Sound travels farther and faster in water than in air, so for true seals, which court mostly in the water, a call can reach females spread over a wide area of sea.
The best-known example is the Weddell seal. Weddell seals in Antarctica sing complex songs.20Wikipedia. Pinniped They use nine recurring call types with pitches above human hearing, which tops out around 20 kHz.21MOO – Antarctica. Weddell Seals Produce Ultrasonic Vocalizations — MOO – Antarctica No other seal, sea lion, or walrus is known to make such ultrasonic calls.22MOO – Antarctica. Weddell Seals Produce Ultrasonic Vocalizations — MOO – Antarctica Harbor seal pups’ calls become more evenly timed as they grow, a little like babbling turning into speech.23PubMed Central. Ontogeny of vocal rhythms in harbor seal pups: an exploratory study
On a beach visit, you’ll hear much less of this. Harbor seals resting on land are mostly quiet, producing only occasional grunts or growls. Gray seals can make moaning or wailing calls on haul-out beaches that many visitors find eerie. Most courtship calling happens beneath the surface, so a quiet beach doesn’t mean the seals aren’t communicating.
Seals That Learn and Copy Sounds
Gray seals can learn to match melodies and copy human vowel sounds by reshaping their own calls.24PubMed. Formant Modification through Vocal Production Learning in Gray Seals That makes seals one of the few mammals besides humans shown to learn new sounds by changing how they shape their throats and mouths.25Journal of Experimental Biology. Singing seals imitate human speech Their vocal tracts resemble ours, so they may help scientists understand how human speech works.26Journal of Experimental Biology. Singing seals imitate human speech27PubMed Central. The role of vocal learning in call acquisition of wild grey seal pups
The most famous example is Hoover, a harbor seal at the New England Aquarium in the 1970s and 1980s who copied human phrases. He sounded like a gruff Boston man, and one phrase people remember was something like “get outta here.” His case was among the first to hint that seals could learn speech-like sounds.
How Boat and Human Noise Changes Seal Calls
Seals adjust their calls to noise, but not all in the same way. Australian fur seals bark faster as boat noise gets louder, and their calls don’t return to normal right after the boat leaves.28PubMed Central. The Behavioural Response of Australian Fur Seals to Motor Boat Noise Wild spotted seals call louder when it’s noisier and lengthen calls at night.29Frontiers in Marine Science. The interaction effects of light and noise on the acoustic parameters of underwater vocalisations of wild spotted seals (Phoca largha) in Liaodong Bay, China Bearded seals call louder only up to a point, then stop increasing even as noise rises.30PubMed Central. Limited vocal compensation for elevated ambient noise in bearded seals: implications for an industrializing Arctic Ocean Male northern elephant seals on a breeding beach don’t raise their calls at all over background noise.31PubMed. High-amplitude vocalizations of male northern elephant seals and associated ambient noise on a breeding rookery
Noise also disrupts behavior. Boat noise of 76 to 80 decibels, around the level of a busy street, made fur seals more watchful and interrupted resting and other vital behavior.32PubMed. Behavioural response of Australian fur seals (Arctocephalus pusillus doriferus) to vessel noise during peak and off-peak human visitation The effect lasted only while the noise was on, but it still signals disturbance.33PubMed. Behavioural response of Australian fur seals (Arctocephalus pusillus doriferus) to vessel noise during peak and off-peak human visitation Calls that get drowned out can also disrupt mother-pup reunions. Near a colony, keep engines low and distance wide.
If you’re watching from shore, stay at least 50 yards (about 45 m) away, the common US guideline, and check local rules because some places require more. If animals lift their heads and stare at you, you are probably too close and should back away. Keep voices low, and don’t throw things or make noise to provoke barking. Never place yourself between a seal and the water, since that blocks its escape route.
Reading a Barking Colony When You Visit
The loudest barking falls in breeding season, when territorial males call most.34Wiley Online Library (Ethology). Seasonal Changes of Vocal Rates and Their Relation to Territorial Status in Male Galápagos Sea Lions (<i>Zalophus wollebaeki</i>) Each species has its own breeding months, so check local timing.
The kind of call tells you more. Deep, repeated honks from a big male usually mean territory, and sudden loud bursts often mark a standoff between males. High, bleating calls are pups calling for mothers. Back-and-forth calling that moves through the crowd suggests a reunion.
Not every quiet seal is in trouble. A seal lying alone on a beach is often just resting. Visible wounds, entanglement, or extreme thinness are concerns, and the right move is to call a local marine mammal stranding network rather than approach. The same goes for a pup you’re worried about. Don’t feed or touch the animal, which is illegal in many places.