South African hominids that lived between around 2.5 million and 1.5 million years ago had an ear for high-frequency consonant sounds, anthropologist Rolf Quam of Binghamton University in New York and colleagues report September 25 in Science Advances.
Using CT scans and digital technology, Quam’s team reconstructed the ear anatomies of two Australopithecus africanus skulls and one Paranthropus robustus specimen. Modern human ear measurements guided virtual recreations of soft tissue around ear bones, enabling calculations of audible sound frequencies.
A. africanus and P. robustus could have heard high-frequency consonants associated with the letters t, k, f and s better than either chimps or present-day people do, the team found. An ability to hear, and presumably make, such sounds enhanced communication among hominids foraging in groups across open landscapes, the researchers propose. Such communication need not have required a humanlike language, only vowel and consonant sounds with shared meanings, they say.