Scientists heard them for the first time
The Weddell seals of Antarctica when they are below the ice make unbelievable, bizarre sounds like trills, whistles, and chirp like droids (robots in Star Wars series). Earlier 34 seal calls audible to human ears were recorded.
Now scientists have installed a special hydrophone (an underwater microphone) in Antarctica’s McMurdo Sound. They heard 9 new types of ultrasonic calls which are totally inaudible to human ears. The range in which the human ear can hear is 20 to 20,000 Hertz (or 20 kiloHertz). Most of the newly heard sounds exceeded 21 kHz, with some reaching 30 kHz and one high pitched shrieking whistle sound reached 49.8 kHz.
The sounds may possibly help them in echolocation (the biological sonar that animals such as dolphins and bats employ to find their way around dark places). Scientists are yet to find the reason for these ultrasonic sounds.
