Male Leopard Seals Sing Underwater Nursery Rhymes For As much as 13 Hours a Day

Leopard seals may not be the primary animal that involves thoughts once we take into consideration singing, however new analysis suggests their songs could have extra in widespread with us than we ever imagined. A research revealed in Scientific Reports discovered that the underwater singing of male leopard seals in Antarctica shares a outstanding structural similarity to the nursery rhymes people sing to kids.

Using information from analog recordings collected within the Nineteen Nineties, researchers analyzed the calls of 26 particular person male seals. They found that these solitary apex predators don’t simply sing randomly, however observe a predictable, repetitive construction made up of 5 key sounds. While these calls are shared throughout a inhabitants, every male arranges them in his personal distinct order, creating a singular sonic “name.”

“Leopard seal songs have a surprisingly structured temporal pattern,” mentioned Lucinda Chambers, lead writer of the research and Ph.D. candidate on the University of New South Wales, in a press release. “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 rhymes.”

Why Do Leopard Seals Sing?

Each spring, male leopard seals start a rigorous and extremely vocal routine throughout the Eastern Antarctic pack ice. They sing solo underwater for as much as 13 hours a day, diving out and in of the ocean in rhythmic two-minute cycles: two minutes submerged singing, adopted by two minutes above water for air, repeatedly. But in contrast to human nursery rhymes, the leopard seal tunes aren’t meant to assuage kids to sleep.

The research means that singing performs a key function throughout the brief breeding season. Female leopard seals are solely fertile for 4 or 5 days a yr, and whereas they could sing briefly throughout this time, they’re surrounded by the nonstop choruses of males vying for consideration. The vocalizations are seemingly tied not simply to mating, but additionally signaling dominance, health, and even particular person id.

“They’re incredibly committed. They’re like the songbirds of the Southern Ocean,” mentioned Tracy Rogers, co-author and professor at UNSW, within the press launch. “You can’t tell them apart by how the call sounds. It’s the order and pattern that matters. They’ve stylized it to an almost boring degree, which we think is a deliberate strategy, so their call carries a long distance across the ice.”

Read More: Here’s Why Dolphins Have to Shout Underwater

Comparing Seal Songs to The Beatles

To higher perceive these songs, researchers measured their construction and in contrast them to vocal patterns from humpback whales, dolphins, squirrel monkeys, and completely different kinds of human music from classical to The Beatles. What stood out was the songs’ similarity to nursery rhymes.

“Nursery rhymes are simple, repetitive, and easy to remember — that’s what we see in the leopard seal songs. They’re not as complex as human music, but they aren’t random either. They sit in this sweet spot that allows them to be both unique and highly structured,” mentioned Chambers within the press launch.

The subsequent section of the crew’s analysis will contain mathematical modeling to find out whether or not these underwater arias act as true vocal signatures just like the whistles utilized by bottlenose dolphins. Additionally, they hope to study extra concerning the evolution and passing down of those songs between generations of leopard seals.

“We want to know if new call types have emerged in the population. And if patterns evolve from generation to generation,” mentioned Chambers within the press launch. “We’d love to investigate whether their ‘alphabet’ of five sounds has changed over time.”

Read More: Are Leopard Seals as Dangerous as You Think?

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