page_title: Pinniped
section_title: Communication
hierarchical_section_title: Pinniped / Behavior and life history / Communication
context_page_description: Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae, Otariidae, and Phocidae. There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage. Pinnipeds belong to the order Carnivora and their closest living relatives are bears and the superfamily of musteloids, having diverged about 50 million years ago.
  Seals range in size from the 1 m and 45 kg Baikal seal to the 5 m and 3,200 kg southern elephant seal male, which is also the largest member of the order Carnivora. Several species exhibit sexual dimorphism. They have streamlined bodies and four limbs that are modified into flippers. Though not as fast in the water as dolphins, seals are more flexible and agile. Otariids use their front limbs primarily to propel themselves through the water, while phocids and walruses use their hind limbs.
context_section_description: Pinnipeds can produce a number of vocalizations such as barks, grunts, rasps, rattles, growls, creaks, warbles, trills, chirps, chugs, clicks and whistles. While most vocals are audible to the human ear, a captive leopard seal was recorded making ultrasonic calls underwater. In addition, the vocals of northern elephant seals may produce infrasonic vibrations. Vocals are produced both in air and underwater. Otariids are more vocal on land, while phocids are more vocal in water. Antarctic seals are more vocal on land or ice than Arctic seals due to a lack of terrestrial and pagophilic predators like the polar bear. Male vocals are usually of lower frequencies than those of the females. 
  Vocalizations are particularly important during the breeding seasons. Dominant male elephant seals advertise their status and threaten rivals with "clap-threats" and loud drum-like calls that may be modified by the proboscis. Male otariids have strong barks, growls, roars and "whickers". Male walruses are known to produce distinctive gong-like calls when attempting to attract females. They can also create somewhat musical sounds with their inflated throats.
  The Weddell seal has perhaps the most elaborate vocal repertoire with separate sounds for airborne and underwater contexts. Underwater vocals include trills, chirps, chugs and knocks. The calls appear to contain prefixes and suffixes that serve to emphasize a message. The underwater vocals of Weddell seals can last 70 seconds, which is long for a marine mammal call. Some calls have around seven rhythm patterns and are comparable to birdsongs and whalesongs. Similar calls have been recorded in other lobodontine seals and in bearded seals. 
  In some pinniped species, there appear to be geographic differences in vocalizations, known as dialects, while certain species may even have individual variations in expression. These differences are likely important for mothers and pups who need to remain in contact on crowded beaches. Otariid females and their young use mother-pup attraction calls to help them reunite when the mother returns from foraging at sea. The calls are described are "loud" and "bawling". Female elephant seals make an unpulsed attraction call when responding to their young. When threatened by other adults or when pups try to suckle, females make a harsh, pulsed call. Pups may also vocalize when playing, in distress or when prodding their mothers to allow them to suckle.
  Non-vocal communication is not as common in pinnipeds as in cetaceans. Nevertheless, when disturbed by intruders harbor seals and Baikal seals may slap their fore-flippers against their bodies as warnings. Teeth chattering, hisses and exhalations are also made as aggressive warnings. Visual displays also occur: Weddell seals will make an S-shaped posture when patrolling under the ice, and Ross seals will display the stripes on their chests and teeth when approached. Male hooded seals use their inflatable nasal membranes to display to and attract females.
caption: Walrus males are known to use vocalizations to attract mates.
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