Why do humpback whale sing- Feeling a Humpback Whale Song Vibrate in Your Chest (with videos and sound)

Two humpback whales swimming together

Introduction

There is nothing more humbling than feeling the powerful song of a humpback whale rumble through your chest.

Being in the water and near a singing humpback whale is not what we’d expect. The serenading, melodic tones of the humpback whale song we know are not how it sounds when you’re floating some 20–30 meters away from a whale singing.

When humpback whales sing, they do so at relatively shallow depths (for them)—about 20–30 meters below the surface—and often near the seafloor (although they can sing in deeper waters too). Swimming from the boat, you can hear the song getting louder as you navigate to where the whale might be. You know when you are close when the sound turns into vibrations. These vibrations move through your body, and you feel it most pronounced in your chest, where the change in medium from tissue (which is mostly water) to the air in our lungs occurs.

Often, we can’t even see the animal while it is at singing depth, but its presence, felt through its song, is most profoundly described as life-changing by many.

The Sounds Up Close

Chirps, gurgles, whistles, and grunts make up the complex sequences of sound produced by humpback whales, and through the mystery of harmonics, these sounds propagate through the ocean and shift into the melodic singing we’ve come to know.

So why does the song, when heard close-up, sound nothing like the melodic version we’ve come to love? The answer is complex, and a sound engineer or physicist would be better at describing why. But I’ll summarize my understanding of it here.

Essentially, the water acts as a low-pass filter. It absorbs the high-frequency energy—the "burp" and "gurgle" texture—leaving only the sustained low fundamental frequency (the smooth, melodic "song") to travel through the "sound channel." High frequencies (which are the textural parts of the sound, such as the burps, gurgles, and chirps) will get absorbed first. The further the sound travels, these high frequencies get filtered out, leaving behind the lower frequencies (which can travel much further in a dense medium like water). This leaves the more melodic tones and the classic "song." I hope this helps, but I’d suggest you go find an expert to explain this better!

WHY? (Theories Behind the Song)

Why humpback whales sing has long been the fascination of whale scientists and the public. Many theories have been put forward, but there seems to be more questions being found each year than answers.

1. It's a Male-Only Phenomenon (But Not Just for Mating) Firstly, it’s just the males that sing. Ah hah! Then it must be a mating call! Well, it turns out when males sing, more males tend to show up to sing as well. Often, a male will join the singer, and it’s suspected this is to check if that male has a female, and thus will potentially try to compete. This new male often leaves when he discovers there's no female present.

2. Mutualism or Communal Effort Secondly, some suggest it might be a form of mutualism, either for attracting others to the area to increase the supply of both males and females to the population, or that this communal singing might be a joint effort by the males to increase the receptivity of the females.

3. A Cultural Phenomenon Finally, the singing might purely be a cultural phenomenon. This is highlighted by the fact that the song changes each year—new phrases are added and then propagate through each population from west to east in the Southern Hemisphere.

Whatever the reason for these humpback whale songs, being in the water while they are singing is an experience few can truly describe. As your body vibrates to the low notes of the whale’s song, you feel small in an ocean surrounded by giant beings.