Bites of Curiosity

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<span  style="font-size: 1.5rem;" >Imagine you are on a scuba diving trip in the Caribbean. The sun is sparkling on the emerald ocean, and you see bright tropical fish darting through the water. Then you start to descend deeper into the sea - and the deeper you go, the more those bright Caribbean colors fade. Although you know that you are still looking at tropical animals, they all start to appear washed out like an old t-shirt. Some frequencies of light (i.e., certain colors) from the sun are better at penetrating water than others – you don’t have to go very deep before all your short-wave reds and yellows are gone and you’ve got nothing but blues. However, the sounds you hear are amplified in the ocean depths (which is why you can communicate by tapping your air tank). As you’re musing about how weird it is underwater, a massive shadow creeps into your peripheral vision. You turn and your breath drops as you watch a hulking whale swim gracefully by. Unlike you, this whale is well suited to life in the ocean. While you’re disoriented without your full sense of vision, the whale’s keen sense of sound makes her right at home.</span>

Whales are very social animals and rely heavily on sound to interact with one another. They use sound to communicate not only with other whales in close proximity to them, but also with whales that are great distances away. You’ve probably heard whale songs in movies or documentaries (check out the Explore More section below if not). All these beautiful notes that have been so mesmerizing to humans have come from either the humpback whale or one subspecies of blue whale. The songs of humpback whales are so haunting that you can actually buy tracks of this music.

But why do whales sing? Is it an art form, the way it is for humans, or does it have a completely different purpose? Although scientists cannot get into the mind of a whale to know exactly what is going on, it is pretty clear that whales use their songs for mating. While all humpback whales communicate vocally, only the males sing. These male songs are quite complex, and include phrases and larger themes. What is even more incredible is that the males in one group of humpback whales will all sing the same song - but that song will change over time based on what they hear from other groups of whales! According to Dr. Ellen Garland, a scientist who researches humpback whale communication, “Our best analogy at the moment is human fashion, where a new look comes about and everyone switches. Or a new pop song comes available and everyone is suddenly listening to it.”¹ In this respect, humpbacks aren’t that different from seventh graders, all singing Beyoncé one summer and all singing Lizzo the next.

We humans naturally form communities with the people physically close to us, because those are the people with whom we can talk. Digital communication has let us (somewhat) expand that community around the globe. Whales have long-distance communication built-in: “a humpback whale singing in the Caribbean, for example, can be heard by a fellow whale off the west coast of Ireland more than 4,000 miles away.”²

How is this possible? According to the National Ocean Service, whale sounds can travel unbelievable distances due to an incredible phenomenon called the sound channel. As we all know, when you dive into water, the temperature decreases as you descend (brr!) and the pressure increases (ouch! Your ears!). When a whale sings, it produces sound waves that move through the water. As these waves travel down, the temperature drops, which causes the waves to decrease their speed and bounce further downwards. But then there is a sweet spot (or really, sweet depth) where the water pressure continues to increase but the temperature doesn’t change. This causes sound waves to increase in speed and bounce back up. This creates a channel at that depth where sound waves are bouncing both up and down, which “allows sound to travel thousands of miles without the signal losing considerable energy.”³ Professor Christopher Clark studies how this all works. He has found that calls close to the surface of the ocean dissipate quickly. However, if the whales are deeper in the ocean and the noises they make enter this layer, their sounds can travel much farther. He says: “That’s how I can hear blue whales singing off the coast of Ireland with a hydrophone placed in the water in Virginia.”⁴

^‍Although we all have access to recordings of whale sounds and may even have seen these giant beasts on a whale watching trip, few of us have had the experience of completely immersing ourselves in the world of whales. Professor Philip Hoare is one of the rare individuals who has been able to do this. Luckily for us, he’s documented his experiences so that we can live vicariously through him.

In The Guardian, Hoare describes a moment when he (perhaps foolishly) decided to jump into the ocean to swim with a group of sperm whales. He did this even though he knew that sperm whales are the only whale species that have eaten humans. When a whale swam directly towards him, he therefore expected either to be swallowed or to be rammed to death. Instead, he had a truly magical experience. He states: “Everything was happening in slow motion. Then I felt- rather than heard- the whale’s sonar moving down my body- click-click-click like an MRI scanner. The sound reverberated through my skull, my sternum, my whole skeleton.”⁵Hoare saw this as a moment of irony due to the fact that “as a writer, I’d spent years trying to describe whales, and here was a whale, trying to describe me.”⁶ What would the whale have told his friends about Hoare?