Dolphin ancestor’s hearing was more like hoofed mammals than today’s sea creatures: CT scan of 30-million-year-old fossil indicates echolocation evolved more than once — ScienceDaily

Paleontologists are looking into the evolutionary origins of the whistles and squeaks that dolphins and porpoises make — part of the rare echolocation ability that allows them to effectively navigate their dark environment.

Source: Dolphin ancestor’s hearing was more like hoofed mammals than today’s sea creatures: CT scan of 30-million-year-old fossil indicates echolocation evolved more than once — ScienceDaily