Researchers studying whales in the western Indian Ocean were stumped. They recorded a whale song never heard before, one described as a “slow, bellowing ballad” by the New York Times. After some underwater sleuthing, they report a happy discovery in the journal Endangered Species Research: The song belongs to a previously undiscovered population of blue whales. This is particularly good news given that blue whales, which grow to gargantuan size, are listed as endangered under the Endangered Species Act, notes a post at Earther. After being hunted to the brink of extinction, the number of blue whales in existence is estimated to be somewhere between 10,000 and 25,000. It’s not clear how many might belong to the new population.
“It was quite remarkable to find a whale song in your data that was completely unique, never before reported, and recognize it as a blue whale,” says study co-author Salvatore Cerchio of the African Aquatic Conservation Fund’s Cetacean Program. Blue whales generally sing low-pitched songs but each population has its own version, explains Science Daily. That’s why researchers were able to identify the new group, which could be a unique subspecies. “It’s like hearing different songs within a genre—Stevie Ray Vaughan versus BB King,” Cerchio tells the Times. “It’s all blues, but you know the different styles.” Researchers say the discovery makes it all the more important to protect the whales with regulations on shipping and carbon emissions. (Read more blue whale stories.)