In a paper published last week in the journal Endangered Species Research, authors described a new whale song, suggesting the existence of a population that was previously unknown. Researchers analysed recordings from three locations in the western Indian Ocean from where they discovered the unique whale song. Why do whales sing, and how does it sound? Not all whales sing. Only some, such as the baleen whale, have been found to sing songs. Whales use songs to communicate and socialise. Their songs can be characterised as clicks, whistles and pulsed calls or a composition of "moans, snores, chirps and cries", as described in Current Biology. According to the US National Oceanic and Atmospheric Administration (NOAA), whales use clicks to navigate and identify their surroundings as the sound bounces off objects, helping whales determine their shapes. Whales use whistles and pulses, on the other hand, during social activities. Can humans hear whale songs? As per Current Biology, whale songs are typically below 4 kHz in frequency (human hearing range is between 20 Hz to 20 kHz). Some blue and fin whale songs are so low in their frequency that parts may be inaudible to human ears. The journal further says whale songs can last between 6-35 minutes, and some individual whales have been found to sing for 22 hours. What is the new song researchers have recorded? Researchers have recorded the unique song off the coast of Oman in the northern Arabian Sea, off the western Chagos Archipalego, and off Madagascar in the southwestern Indian Ocean. Since it is the only blue whale song identified by them in the western Arabian Sea, researchers have called it the “Northwest Indian Ocean”. Researchers believe the source is either the blue whale or Bryde's whale since both species have been documented off Oman previously. "Given that this song-type has not been reported before, the presence of it across a large geographic region indicates the likely existence of a previously undefined population of blue whales in the Western Indian Ocean," they noted. "Our observation and initial assessment of this new song-type/acoustic population, and thus potentially a distinct biological population of blue whales in the northwestern Indian Ocean, should lead to dedicated research to better understand it, particularly in light of the conservation implications," they added.
