Blue whales

Context:

• Researchers have recorded, reportedly for the first time from the waters off Kerala, the song of blue whales.
• A hydrophone deployed off Vizhinjam to capture the sounds of migrating humpback whales had instead recorded the call of the endangered blue whale.
• While humpbacks are known for their high-frequency vocalisations, blue whale songs are a series of short, low-frequency moans.
• Whale sounds (moans, cries, chirps and cries) are essentially communication tools, for activities such as socialising and mating.
• Call patterns can vary from population to population.
• So far, the presence of blue whales in the waters off Kerala have been reported through a few carcasses that beached. But the recording of their calls confirms their presence along this stretch of the western coast.

About blue Whales:

• The blue whale was once abundant in nearly all the Earth's oceans until the end of the 19th century.
• It was hunted almost to the point of extinction by whalers until the International Whaling Commission banned all blue whale hunting in 1966.
• The International Union for Conservation of Nature has listed blue whales as endangered as of 2018.
• It continues to face numerous threats, both man-made (ship strikes, pollution, ocean noise and climate change), and natural (killer whale predation).
• The blue whale is the largest known animal to have ever existed.

Pygmy blue whales

• Though the larger blue whale populations are found around Antarctica where krill, their favourite food, is available, the occurrence of pygmy blue whales is reported in the Indian Ocean.

https://www.thehindu.com/news/national/kerala/blue-whales-sing-off-kerala-coast/article35448764.ece?homepage=true