Seals are fun animals; they look and act cute, but they are perfectly capable of ripping their game or curious humans to shreds in a matter of mere seconds.
Seals might be awkward looking, they almost look like they shouldn't be able to thrive in the fierce and competitive antarctic meta, or anywhere for that matter, but lest we forget, they are capable of diving 2,000 ft (600 mt) below the surface and staying there for up to 80 minutes.
Seals have two modes of communication — above and underwater
Above the surface, they sound like flatulent Chewbaccas, and underwater, they use a completely different mode of communication: High pitched shrieks inaudible to human ears. Now, a recent study published in The Journal of the Acoustical Society of America revealed that there's more to their calls.
Paul Cziko, the lead author of the study and a visiting professor at the University of Oregon, told in a press release that "The Weddell seals' calls create an almost unbelievable, otherworldly soundscape under the ice," and noted that they would often fall asleep listening to otherworldly pew-pews. "It really sounds like you're in the middle of a space battle in 'Star Wars,' laser beams and all," he said.
A staggering 200 kilohertz recorded
After installing a new hydrophone (a microphone for underwater) in 2017, they began picking up on even more higher-pitched vocalizations coming from these sea animals. Previously, we knew of 34 distinct calls. All of these fall inside the human hearing range — which is roughly 20 hertz to 20 kilohertz (kHz). And the new study details 9 more with whistles, trills, and alienesque chirps — some of their vocalizations even utilize overtones, creating polyphonic sounds. And all these newfound sounds fall outside our hearing range.
Some of these new sounds had a fundamental frequency that consistently hit around 30 kHz and there was one among them that hit a staggering 49.8 kHz — he or she was possibly the Ariana Grande or Mariah Carey equivalent of a Weddell seal perhaps, but who knows. When they stacked overtones, the team noted that they could reach above 200 kHz. This is well above what doggies and cats can hear, even some bats don't hear that high.
It's cool and all that, but what function these calls serve? The team behind the study is not sure. It's the first time we're detecting ultrasonic vocalizations in fin-footed animals (like walruses, seals, or sea lions). Cziko speculates that it could just be a different register to make what you say stand out above usual chatter.
It's a theoretical possibility that these may be for echolocation purposes (think bats or dolphins), but we can't be sure at this point. Still, it makes it a viable explanation since in Antarctic winter, 2,000 ft (600 mt) below the ice sheet, you wouldn't have much use for your sense of vision.
You can listen to the recordings brought down to a perceptible frequency from the supplementary materials section of the publication. The filename for the demonstration paired with a video is: supppubmm3.mp4