In the cathedral of ice beneath Antarctica’s frozen sea, male leopard seals conduct their solitary concerts. Day after day, sometimes for 13 hours straight, these predators plunge into the frigid waters, calling out in moans and chirps as loud as a jet plane. They emerge only to refill their lungs before diving back down to transmit their message across the vast Antarctic seascape. “They’re like the songbirds of the Southern Ocean,” said Tracey Rogers, a professor at the University of New South Wales (UNSW) in Australia, who has collected leopard seal sound recordings since the 1990s. “During the breeding season, if you drop a hydrophone into the water anywhere in the region, you’ll hear them singing.” She added, “They’re incredibly committed.” A new study, published in Nature, analyzed the underwater vocalizations of 26 male leopard seals (Hydrurga leptonyx) in the Davis Sea along Eastern Antarctica’s pack ice. Scientists used a mathematical model called “information entropy” to measure the predictability of these notes and sounds and how they compare to other mammal calls, including human music ranging from the Beatles to Bach. They found that leopard seal mating calls are similar in predictability to human nursery rhymes. A leopard seal on an iceberg. Photo courtesy of Vivek Mehra / Ocean Image Bank “When we compared their songs to other studies of vocal animals and of human music, we found their information entropy — a measure of how predictable or random a sequence is — was remarkably close to our own nursery…This article was originally published on Mongabay

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