Over two years of recording at the underwater observatory in McMurdo Sound, nine types of tones were recorded.
Weddell seals (Leptonychotes weddelii), the southernmost mammals in the world, live undersea ice of Antarctica, using large teeth to create air holes. They can dive to a depth of 600 meters in search of prey and remain underwater for 80 minutes. Researchers first identified 34 types of seal calls at audio frequencies in 1982, linking different sounds to different types of social interactions.
Study lead author Paul Chico, guestresearch professor at the UO Institute of Ecology and Evolution, began recording seal vocalizations in 2017 following the completion of the McMurdo Oceanographic Observatory.
Over the next two years, broadbandThe observatory's digital hydrophone—more sensitive than equipment used in earlier recordings—picked up high-frequency vocalizations while passively monitoring the seals. In general, seal sounds were above 20 kHz. Although the overtones of some seal vocalizations exceeded 200 kHz.
What do ultrasound vocalizations mean inthe repertoire of Weddell seals is unknown. Seals belong to 33 species of water-legged mammals belonging to the pinnipeds. Until now, it was believed that pinnipeds, including sea lions and walruses, only emit sound signals.
However, scientists suggest that ultrasoundVocalization can be used for echolocation, a biological sonar that dolphins, toothed whales, and bats use to navigate in low-visibility conditions to avoid obstacles and find friends or prey.
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