Although blue whales are the largest marine animals in existence, they are notoriously elusive. But scientists at the University of New South Wales (UNSW) in Australia believe they’ve discovered a whole new population in the central Indian Ocean.
The new population is made up of an unknown number of pygmy blue whales. Pygmy blue whales, as their name suggests, are the smallest subspecies of blue whales. In this context, however, “small” is a relative term. Their beefier parents might outshine them by tens of inches and pounds, but pygmy blue whales can still reach 24 meters (around 79 feet). That’s almost the length of two standard buses, according to the UNSW press room.
“We don’t know how many whales make up this group, but we think it’s a lot by the huge number of calls we hear,” UNSW professor and lead author Tracey Rogers told the newsroom. of the study.
Rogers and colleagues published their analysis in the scholarly journal Scientific reports April 22. If visual sightings confirmed their findings, the new pygmy blue whale population would be the fifth to be identified in the region, according to the editorial staff.
Rogers and his colleagues were reviewing data gathered by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), a collective formed in 1996 to monitor nuclear bomb tests when their suspicions were aroused. One of the most useful weapons in the CTBTO arsenal is the hydrophone, a sophisticated technology that essentially functions like an underwater microphone. Hydrophones record the sound waves created by nuclear bomb testing, but they also pick up many other noises, including those emitted by marine animals.
During their examination, Rogers and his colleagues heard a whale song that differed from those sung by the three populations of blue whales and the four populations of Omura whales known to inhabit the area. Far from being interchangeable, whale songs are unique in sonic characteristics such as tempo, structure and frequency, according to the newsroom.
“We still don’t know if they were born with their songs or if they learned it,” Rogers said. “But it is fascinating that in the Indian Ocean animals cross paths all the time, but whales from different regions still retain their distinctive songs. Their songs are like a fingerprint that allows us to follow them when they are travel thousands of kilometers. “
Marine biologists estimate that less than 0.15% of blue whales in the southern hemisphere have survived the whaling age. Their numbers, Rogers said, are still recovering.