Auditory sensitivity between 0.5-5.0 kHz for chimpanzees, humans and the early hominins. Points higher on the curve indicate greater auditory sensitivity. (A) Region of maximum sensitivity. The early hominins are shifted toward slightly higher frequencies compared with chimpanzees. (B) Hearing results. The early hominins show a distinct auditory pattern. They are more sensitive than either chimpanzees or humans up to around 3 kHz. Above around 3.5 kHz, the early hominins resemble chimpanzees more closely in showing a dropoff in sensitivity.