Seals, aquatic mammals known as pinnipeds, exhibit a diverse range of vocalizations. Though often perceived as silent, these creatures are quite vocal, using sound as a primary means of interacting with their environment and each other. Their vocal repertoire plays a significant role in their daily lives both on land and in the water.
A Symphony of Seal Sounds
Seals produce varied vocalizations. Many species emit barks, growls, honks, moans, and grunts on land or at the surface. Harbor seals, for example, use barks, tonal honks, grunts, growls, roars, and moans in air, and a distinctive underwater roar.
Elephant seals, particularly males, produce loud, guttural vocalizations; females may burp and pups squeak. Weddell seals use chirps, whistles, and ultrasonic calls, some beyond human hearing. Gray seals make growls, throaty sounds, clicks, knocks, and roars underwater, and can “clap” their front flippers to create sounds. Leopard seals are known for their underwater songs, composed of five distinct call types.
The Purpose Behind the Calls
Seals vocalize for various reasons, primarily communication. They use sounds to interact with other seals, convey warnings, and establish or defend territories. During breeding seasons, males use acoustic displays to attract mates and assert dominance. For example, male harbor seals use underwater roars to defend their breeding territories.
Vocalizations are important for mother-pup bonding, helping mothers and pups recognize each other amidst crowded colonies. Pups are particularly vocal and can adjust the pitch of their calls in noisy environments to ensure their mothers hear them. Seals also use sounds to express distress, excitement, or to warn others of potential predators.
How Seals Produce Their Unique Sounds
Seals produce airborne sounds using their larynx and vocal cords, similar to other mammals. Air from the lungs passes through the vocal folds, causing them to vibrate and generate sound. The shape and tension of these vocal cords, along with the configuration of their vocal tract, influence the resulting sound.
For underwater vocalizations, seals have adapted specialized mechanisms. Some species produce sounds without exhaling air, by recirculating air within their respiratory system or utilizing specialized vocal sacs. Their skull and nasal passage structures also modify sound resonance and projection. For instance, the prominent proboscis of elephant seals influences their distinct vocalizations.