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The descended larynx is not uniquely human
1Department of Psychology, Harvard University, 33 Kirkland Street, Cambridge, MA 02138, USA. tec@wjh.harvard.edu
Proceedings. Biological Sciences
|August 17, 2001
Summary
The descended larynx, once thought unique to humans for speech, is also found in deer. This vocal anatomy adaptation likely evolved to exaggerate body size, not just for language.
Area of Science:
- Evolutionary biology
- Bioacoustics
- Functional morphology
Background:
- Morphological variations in vocal anatomy are crucial for understanding communication evolution.
- The descended larynx in humans has been linked to speech and language evolution.
- The uniqueness of a descended larynx in humans has been a key assumption in hominid evolution studies.
Purpose of the Study:
- To investigate the presence and function of a descended larynx in non-human animals.
- To challenge the assumption that a descended larynx is exclusively human and linked to speech.
- To explore alternative adaptive functions for laryngeal descent.
Main Methods:
- Bioacoustic analyses of vocalizing animals.
- Anatomical analyses of functional morphology.
- Comparative study of vocal anatomy in deer and humans.
Main Results:
- Descended larynges were documented in male red and fallow deer.
- The resting laryngeal position in deer is similar to humans.
- Red deer stags further lower their larynx during roaring, similar to human vocalizations.
Conclusions:
- Laryngeal descent is not unique to humans and has evolved independently in different lineages.
- Laryngeal descent elongates the vocal tract, potentially exaggerating perceived body size by lowering resonant frequencies.
- Size exaggeration presents a non-linguistic adaptive hypothesis for laryngeal descent in human evolution.
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