Scientists have made a groundbreaking discovery about how some of the largest whales in the ocean produce their haunting and complex songs. The study, led by Prof Coen Elemans from the University of Southern Denmark, has also shed light on why human-made ocean noise disrupts these ocean giants. The research, published in the journal Nature, reveals that humpbacks and other baleen whales have evolved a specialized “voice box” that allows them to sing underwater. This vocal anatomy enables them to recycle air and prevents water from being inhaled, allowing them to produce their unique songs.
Baleen whales, including species such as the blue, humpback, right, minke, and gray whale, do not have teeth. Instead, they have plates of baleen, which they use to sieve tiny creatures from the water. The mechanism behind their complex songs has long been a mystery, but the recent study has provided answers. The researchers conducted experiments using larynxes, or “voice boxes,” from three stranded whale carcasses – a minke, a humpback, and a sei whale. By blowing air through these structures, they were able to produce the sounds made by the whales.
In humans, our voices come from vibrations when air passes over vocal folds in our throat. However, baleen whales have a different vocal anatomy. They possess a large U-shaped structure with a cushion of fat at the top of their larynx. This unique structure allows them to sing by recycling air and prevents water from being inhaled. The researchers created computer models of the sounds produced by the whales and discovered that their songs are restricted to a narrow frequency that overlaps with the noise produced by shipping vessels.
According to Prof Elemans, sound is crucial for the survival of these whales as it is the only way they can find each other to mate in the vast ocean. However, human-made ocean noise disrupts their ability to communicate over long distances. This knowledge is vital for the conservation of endangered giants like humpbacks and blue whales. It also provides insight into the mysterious and eerie songs that these animals produce, which sailors used to attribute to ghosts or mythical sea creatures.
Dr Kate Stafford, a whale communication expert from Oregon State University, hailed the study as groundbreaking. She emphasized that understanding how whales produce sounds is crucial for advancing the field of marine mammal research. The study also sheds light on the evolutionary journey of whales from land to sea and the adaptations that allowed them to communicate underwater.
Toothed whales, such as dolphins, orcas, sperm whales, and porpoises, produce sound by blowing air through a special structure in their nasal passages. This mechanism is better understood because these animals are easier to study. However, studying large baleen whales presents significant challenges, as they are difficult to observe underwater while vocalizing. The researchers behind this study had to be creative in their approach to uncovering the secrets of whale song production.
The ability of baleen whales to produce such complex vocal signals is remarkable and highlights the unique nature of these animals. The study not only deepens our understanding of whale communication but also raises awareness about the impact of human-made ocean noise on these majestic creatures. By recognizing the importance of sound for their survival, we can take steps to mitigate the disruption caused by our activities and ensure the conservation of these endangered giants of the sea.
