Antarctic Blue Whale – Balaenoptera musculus intermedia
Spectrogram of Z-call
Note: Some of these sounds are below the human hearing range and hence inaudible unless sped up.
Gavrilov, A., McCauley, R., and Gedamke, J. (2012). Steady inter and intra-annual decrease in the vocalization frequency of Antarctic blue whales. The Journal of the Acoustical Society of America, 131(6), 4476-4480.