and this is where nan hauser has made some of her most beautiful discoveries. >> hauser: here, we seeding on his head, upside down, singing a song. they are motionless and the song bellows out. >> pelley: the humpback song can be 20 minutes long, and they repeat the same song again and again. males in one region will all sing the same song the same way. but next year, they'll return with a new composition. so, this is air somehow moving around inside their heads? that's making this sound, even though they don't have vocal cords? >> hauser: correct. it's almost, i think, like taking a balloon full of air and going.... >> pelley: the sound carries for miles. and hauser believes, it's all to mark their territory. >> hauser: they take turns singing, perhaps to say, "my lungs are bigger. i can hold my breath longer. i can sing a more beautiful song. i'm the dominant male. i'm going to sing here so you move away and sing somewhere else. >> pelley: can you do some of the sounds that you've heard? >> hauser: i think the most common whale sound is kind of a... but we get everything. we've even

. 80% of their lives spent submerged and this is where nan hauser has made some of her most beautifulhere we see a male standing on his head upside down singing a song. (whale singing) they are motionless and the song bellows out. >> pelley: the humpback song can be 20 minutes long and they repeat the same song again and again. males in one region will all sing the same song the same way. but next year they'll return with a new composition. so this is air somehow moving around inside their heads that's making this sound in >> correct. >> pelley: even though they don't vocal chords? >> correct. it's like taking a balloon full of air and going whee! (laughs) >> pelley: the sound carries for miles and hauser believes it's all to mark their territory. >> they take turns singing. perhaps to say "my lungs are bigger, i can hold my breath longer, i can sing a more beautiful song, i'm the dominant male. i'm singing here, you move away and sing somewhere else." >> pelley: can you do some of the sounds that we've heard that >> i think most common whale sound is kind of a (sings in humpback) we