Voice control: Why North Atlantic right whales change calls as they age

Source: Science Daily

Through extensive listening and analysis of whale calls — which were recorded by a large collaboration of scientists over the past two decades — researchers were able to pick up the slow gradual changes in sound production in the marine giants as they age. Looking at spectrograms of the calls, which provide visual representations of the sound, the research team could see the progression of vocal characteristics of the animals from calf throughout adulthood.

https://www.sciencedaily.com/releases/2018/02/180227090559.htm