SYDNEY, Aug. 1 (Xinhua) — Australian researchers have discovered that Antarctic leopard seals’ underwater “songs” share structural patterns with human nursery rhymes.
Analyzing recordings collected since the 1990s, scientists from Australia’s University of New South Wales (UNSW) found that leopard seal “songs” are repetitive and predictable, much like children’s nursery rhymes, according to a UNSW statement released on Friday.
Called the “songbirds” of the Southern Ocean, male leopard seals spend up to 13 hours a day singing underwater solos each spring, surfacing and diving in two-minute cycles, researchers said.
“During the breeding season, if you drop a hydrophone into the water anywhere in the region, you’ll hear them singing,” said the study’s co-author, UNSW Professor Tracey Rogers.
Male seals build their “songs” from five shared “notes,” with each individual identified by the unique order of these sounds, according to the findings detailed in Scientific Reports published by Nature.
Researchers revealed that leopard seal “songs” match the predictability of nursery rhymes, based on an analysis of information entropy, an indicator of how structured or random a sequence is.
This simplicity allows their calls to carry efficiently across vast Antarctic distances, helping the seals claim territory and attract mates, in contrast to the more intricate vocalizations of humans or other marine mammals like humpback whales and dolphins, the study showed.
“It’s a bit of a dual message. It could be a ‘this is my patch’ to other males and also a ‘look how strong and lovely I am’ to the females,” Rogers said.
With decades of technological advancement, researchers are set to investigate if these unique call patterns help seals recognize each other and whether their “alphabet” of five sounds changes over generations. ■