A 26-Million-Year-Old Whale Song

Comparison of inner the inner ear bone (cochlea) of a xenorophid, left, and a modern-day dolphin, right. (Credit: Museum Victoria/Ben Healley)  Modern whales and dolphins navigate in the oceans using echolocation, a system that bounces sounds off objects to reveal their details and distance. These magnificent marine mammals use their distinctive, high-frequency sounds for communicating with each other and hunting prey. The development of this important sensory system was a crucial factor in the evolution of odontocetes, the group that includes toothed whales and dolphins. Now, an international team of researchers has discovered when this key adaptation evolved in their now extinct ancestors.