Primitive whales had mediocre hearing
Fossils suggest highly specialized sounds whales use to communicate were not an early innovation
Early on, whale hearing may have been ho-hum.
Unlike today’s whales that specialize in making — and hearing — very high- or low-pitched sounds, early whales’ ears probably picked up noises somewhere in the middle, paleontologists Mickaël Mourlam and Maeva Orliac report June 8 in Current Biology.
Looking at CT scans of ancient whale ear bones allowed the researchers, from the University of Montpellier in France, to weigh in on a long-standing debate over the evolution of whale hearing. At the heart of the controversy is when whales got their super-hearing abilities. Those abilities allow today’s whales to chitchat long distance and use sound to locate prey with calls that fall under the radar of human ears.
Modern toothy whale species such as orcas specialize in high-frequency sounds, while humpbacks and other baleen species are great at detecting low-pitched noises. Toothed and baleen whales split around 35 million years ago, and paleontologists have speculated that the early whales already had some form of extreme hearing — either high or low, depending whom one asks (SN Online: 08/05/16). Both camps might be wrong, the new finding suggests.