Explained: the significance of the new whale song recorded in the Indian Ocean

In an article published last week in the magazine Research on endangered species, the authors described a new whale song, suggesting the existence of a previously unknown population. The researchers analyzed records from three locations in the western Indian Ocean from where they discovered the only whale song.

Why do whales sing and how does it sound?

Not all whales sing. Only a few, such as the boy whale, have been found singing songs.

Whales use songs to communicate and socialize. Their songs can be characterized as clicks, whistles and pulsing calls or a composition of “moans, snores, chirps and screams”, 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 sound bounces off objects, helping whales determine their shape. Whales use whistles and pulses, on the other hand, during social activities.

Can humans hear whale songs?

As per Current biology, whale songs typically have a frequency below 4 kHz (the range of human hearing is 20 Hz to 20 kHz). Some blue whale and fin whale songs are so low in their frequency that parts may not be audible to the human ear. The diary further states that whale songs can last between 6-35 minutes and that some individual whales have been found singing for 22 hours.

What is the new song that the researchers recorded?

The researchers 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. Because it is the only blue whale song they identified in the western Arabian Sea, the researchers called it the “Northwest Indian Ocean.”

Researchers believe the source is the blue whale or Bryde’s whale as both species have previously been documented off the coast of Oman. “Since this type of song has not been reported before, its presence in a large geographic region indicates the likely existence of a previously undefined blue whale population in the western Indian Ocean,” they noted.

“Our initial observation and evaluation of this new type of song / 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 implications for conservation, “they added.