A new study published in the journal *Current Biology* reveals new clues about how whales and dolphins came to use echolocation, the ability to use sound waves to navigate and find prey.

Echolocation is a highly specialized sense that allows whales and dolphins to "see" their surroundings in a way that is completely different from humans. They emit high-pitched clicks or whistles that bounce off objects in their environment and return to their ears. By analyzing the echoes, they can determine the size, shape, and location of objects, even in complete darkness or murky water.

How whales and dolphins evolved this ability has long been a mystery, but the new study provides some important insights. The researchers analyzed the ear bones of early whales and dolphins, as well as the ear bones of their terrestrial ancestors, such as mesonychians and pakicetids. They found that the ear bones of early whales and dolphins underwent a series of changes that improved their ability to hear high-pitched sounds. These changes included the development of a specialized bone called the malleus, which acts like a hammer to amplify sound waves, and the elongation of the cochlea, which is responsible for processing sound information.

The researchers believe that these changes in the ear bones allowed early whales and dolphins to gradually develop echolocation. As they adapted to living in the ocean, they began to rely more and more on sound to navigate and find food. Over time, their echolocation abilities became more refined and sophisticated, allowing them to become some of the most successful predators in the ocean.

This study provides new evidence for the evolutionary origins of echolocation in whales and dolphins. It also helps us to better understand how these amazing animals are able to navigate and interact with their environment.