A fascination with the rhythmic and haunting sounds of humpback whale songs led bioacoustician Eduardo Mercado on a quest to understand their true purpose. Contrary to the common belief that these songs serve as mating calls, Mercado speculated whether the whales were using them for echolocation, akin to dolphins. This curiosity sparked years of research culminating in Mercado’s book “Why Whales Sing,” where he delves into the enigma of whale communication.
Whale songs, unlike human or bird songs, lack a definitive start or end. Baleen whales, including humpbacks, emit continuous sounds for hours, cycling through fixed patterns in what Mercado describes as an ongoing acoustic carousel. Challenging the traditional view of whale songs as displays for other whales, Mercado proposes that they serve as a sophisticated form of echolocation, allowing whales to navigate their surroundings independently.
While many scientists argue that whale songs are courtship rituals, Mercado points out the evolving nature of the sounds over time, suggesting a more utilitarian function related to echolocation. Drawing parallels between whale and bat echolocation, Mercado conducted experiments to demonstrate the feasibility of whales detecting objects kilometers away using their songs.
Through his research on sound processing in mammalian brains, Mercado explored the remarkable range of whale vocalizations, with humpback sounds traveling up to 100 kilometers and other whale species’ songs detected over 1,000 kilometers away. By analyzing the physics of sound propagation and the purpose of extreme loudness in echolocation, Mercado sheds light on whales’ ability to detect large moving targets.
In Mercado’s view, whales use their sonar abilities to monitor the behaviors of distant whales, crucial for their nomadic lifestyle and transient social interactions. The cessation of singing when whales begin to swim indicates a shift in focus towards specific actions based on gathered information. Ultimately, for whales, sound serves as a tool for navigating vast oceanic expanses and understanding the movements of their solitary counterparts.