Hearing Sensitivity

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True   Likely   Speculative
Human Uniqueness Compared to "Great Apes": 
Relative Difference
Human Universality: 
Individual Universal (All Individuals Everywhere)
MOCA Domain: 
MOCA Topic Authors: 

Humans on average can hear up to 20 KHz whereas an average chimpanzee can hear close to 30 KHz. Using sophisticated algorithms to predict acoustic frequencies and the transmission probabilities depending upon the morphology of hearing organs (ear pinna, bones, auditory canal, etc), it is well documented that a logarithmic plot of bodyweight versus acoustic frequency shows an inverse relationship for primates. However, humans are mild outliers using a comparatively lower acoustic frequency for communication. Given the body mass and close evolutionary relationships of humans and chimps, the highest audible acoustic frequencies should be comparable. The evolution of the human acoustic frequency range can give insights about the ecological (geographical, interspecific, and intraspecific interactions) constraints acting upon them.


Timing of appearance of the difference in the Hominin Lineage as a defined date or a lineage separation event. The point in time associated with lineage separation events may change in the future as the scientific community agrees upon better time estimates. Lineage separation events are defined in 2017 as:

  • the Last Common Ancestor (LCA) of humans and old world monkeys was 25,000 - 30,000 thousand (25 - 30 million) years ago
  • the Last Common Ancestor (LCA) of humans and chimpanzees was 6,000 - 8,000 thousand (6 - 8 million) years ago
  • the emergence of the genus Homo was 2,000 thousand (2 million) years ago
  • the Last Common Ancestor (LCA) of humans and neanderthals was 500 thousand years ago
  • the common ancestor of modern humans was 100 - 300 thousand years ago

Possible Appearance: 
6,000 thousand years ago
Probable Appearance: 
6,000 thousand years ago
Definite Appearance: 
100 thousand years ago
Background Information: 

Acoustic signals are used for various purposes by animals, the most notable being communication, hunting, courtship, and environment sensing. The primate ear is sensitive to only a particular frequency range. If the receptivity of the ear for a particular frequency range shifts, it can lead to poor vocalization skills, disadvantages in courtship, and environment sensing. 

The Human Difference: 

Humans’ highest frequency (20 KHz) is ~10 KHz lower than the Chimpanzee high-end frequency, although the deviation is comparatively low. It is possible that the frequency difference is due to non-functional ear pinna. Addition information about the ear structure of other hominins is needed for conclusive evidence.

Universality in Human Populations: 

It is universal throughout human populations,  although certain studies suggest that infants have a higher frequency reception than adults. This might suggest a developmental trajectory of retained ancestral sensitivity. However, it should be noted that most mammalian infants have a higher frequency range as compared to adults.

Mechanisms Responsible for the Difference: 

One possibility was the availability of acoustic frequency bands in ancestral ecological niches. This would imply that high frequency acoustic signals were already in use by other species in the vicinity, and as such shifting to a lower frequency avoided acoustic signal overlap. Another possibility could include sexual selection as cohabitating hominids used higher frequencies.

Implications for Understanding Modern Humans: 

This may provide insights into the acoustic environment in which humans evolved.


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  3. Primate auditory diversity and its influence on hearing performance., Coleman, M. N., and Ross C. F. , Anat Rec A Discov Mol Cell Evol Biol, 11/2004, Volume 281, Issue 1, p.1123-37, (2004)
  4. The Role of Body Size, Phylogeny, and Ambient Noise in the Evolution of Bird Song, Ryan, M. J., and Brenowitz E. A. , The American Naturalist, Volume 126, Issue 1, p.87-100, (1985)