The haunting sound of whales singing can be a soothing soundscape that can help people relax, or it can evoke a sense of eeriness if you’re going to be alone in the open ocean at night. When whales sing, we think they communicate with complex, beautiful songs that echo for miles through the water.
Whale song has fascinated humans for decades, but the true purpose and mechanisms behind it have long remained a mystery. Now advances in underwater acoustic recording technology and whale research are pulling back the curtain on the secret lives of singing whales.
Scientists have identified several possible functions of whale song, including attracting mates, navigation, communicating over long distances, and expressing emotions. Male humpback whales are known for their complex songs lasting up to 30 minutes, which they repeat for hours during mating season. This suggests that whale song plays an important role in courtship.
Meanwhile, blue whale songs contain identifiable patterns shared by all whales in a population across large oceanic regions; This is evidence that songs can function for large-scale communication and coherence within social groups. Songs also appear to drive gray whale migration, with different types of songs sung at different stages of their epic journey up the Pacific coast.
So how exactly do whales create their spiritual choruses? Their anatomy provides some clues. Toothed whales, such as orcas and sperm whales, have a single nasal passage that connects their blowhole to their larynx. They use the larynx to block and seal the airway while underwater and produce sounds using a vocal organ in their nasal passages.
Mammals, including humans, have folds of tissue that we call vocal cords. These are located in a special area called the larynx.
As air is exhaled from the lungs, pairs of folded tissues in the larynx vibrate, creating sound. Baleen whales, such as humpback whales and blue whales, have two nasal passages that are thought to play a role in song production.
These passageways connect to the laryngeal sacs, which are surrounded by muscles that can vibrate to modulate sound. To discover how whales make sounds, a team of scientists examined the larynxes of three different species of baleen whales: sei, humpback and minke whales. They then created an air source to mimic a whale’s lungs. Sound was produced by blowing air between a fatty pad and the surface of the vocal cords.
Whales have extraordinarily large brains. Interestingly, the largest whale, the blue whale, does not have the largest brain. Although blue whales can measure anything up to 90 ft long, their brains weigh around 7 kg (15 lb). However, the sperm whale weighs about 9 kg. By comparison, an adult human brain weighs about 1.4 kg, while an elephant brain weighs about 5 kg.
The whale brain has entire lobes devoted to auditory processing, perfect for creating and analyzing the nuances of complex whale songs. It is the only mammal whose ears are adapted to work underwater. They also operate at low frequencies, ideal for long-distance communication. The ears also “float” inside their heads, so they can tell which direction the sound is coming from.
Advanced technologies are providing new insights into the acoustic qualities of whale songs. Directed hydrophones can trace songs back to individuals, while acoustic tags attached to whales record data on song use and production.
Specialized software can then visualize whale song, providing tantalizing indications that whales combine such song elements into hierarchical sequences like the structures we see in human language. This raises profound questions about whales’ linguistic abilities.
We know that whales can hunt in packs, and this requires a level of communication to organize themselves so that not all of the prey escapes. They can track, isolate and eventually capture their prey. We believe whale song allows whales to communicate and coordinate their hunting.
Whale song represents a complex form of culture and communication that we are only beginning to grasp. Each population has its own unique musical dialect that is passed down between generations for reasons that are still largely mysterious to us.
Uncovering the secrets of whale songs could shed light on their behavior, social structure and intelligence.
But time may be running out to understand these wonderful marine mammal ballads. Noise pollution, climate change, hunting and ship collisions increasingly threaten song whales. As fragile acoustic environments and whale populations change rapidly, recording whale songs takes on new urgency.
If we listen carefully to whale songs, wonders about both our world and the whales’ world can be revealed. But first, we must ensure that these unforgettable melodies continue to resonate deeply for future generations.
Dr James Williams is a senior lecturer in education at the University of Sussex.