When male leopard seals dive into the icy waters of Antarctica, they produce melodies resembling children’s songs. These melodies can last up to 13 hours, according to a study published Thursday in the journal Scientific Reports.
An Australian research team analyzed the structure of the singing of this species compared to songs of other animals, as well as melodies by musicians like The Beatles and Mozart.
Lucinda Chambers, a PhD student in bioacoustics at the University of New South Wales and the study’s lead author, noted in an interview with Agence France-Presse that people are often surprised by the “unusual” calls and whistles of leopard seals, likening them to sound effects from a 1980s science fiction film.
During the spring breeding season, male seals dive and “sing” for two minutes before surfacing to breathe, repeating this for up to 13 hours a day.
Researchers found that all leopard seals use the same five “notes.” However, each male arranges these notes uniquely to compose its own song.
Chambers stated, “We believe they use this structure to announce their identity, as if calling their name into the air.”
Scientists suggest that males use these songs to attract females and ward off competing males.
“Ocean Nightingale”
The team analyzed recordings of 26 leopard seals captured in the 1990s. Co-researcher Tracy Rogers from the University of New South Wales recorded these during her studies on the eastern coast of Antarctica.
Rogers remarked, “They’re like the southern ocean nightingales.” She added, “During the breeding season, if you drop a sound device in the water anywhere in the area, you’ll hear them singing.”
Analysis of the sequence of tones showed that leopard seal songs are less predictable than humpback whale songs or dolphin whistles, but more predictable than the complex music of The Beatles or Mozart.
Chambers explained that their songs fall into a category resembling those sung by children, which makes sense as they are expected to be simple enough for each leopard seal to remember and repeat daily.
She compared it to “children’s songs that have to be predictable enough for a child to memorize.”
At the same time, each song must have enough uniqueness to distinguish it from the songs of other males.
Leopard seals, which are the primary predators in Antarctic waters, are solitary creatures that roam vast areas. Researchers propose that their singing may have evolved to reach long distances as well.
Chambers noted that changing pitch or frequency wouldn’t be as effective in such an environment.
Female leopard seals also occasionally sing, although the reason for this is not clear. Researchers speculate that their singing may serve an educational purpose for their young, though such behavior has not been observed in wild animals. Another hypothesis suggests it could be a means of communication among them.
