Answers.Body: <p>Gorillas have laryngeal air sacs that extend over the top of their chests.</p>
  <p>Nishimura, T., Mikami, A., Suzuki, J., &amp; Matsuzawa, T. (2007). Development of the laryngeal air sac in chimpanzees. International Journal of Primatology, 28, 483-492. <a href="https://https:/doi.org/10.1007/s10764-007-9127-7" rel="nofollow noreferrer">https:/doi.org/10.1007/s10764-007-9127-7</a> (<a href="https://www.researchgate.net/profile/Akichika-Mikami/publication/225148707_Development_of_the_Laryngeal_Air_Sac_in_Chimpanzees/links/5418f3de0cf25ebee98828e9/Development-of-the-Laryngeal-Air-Sac-in-Chimpanzees.pdf" rel="nofollow noreferrer">PDF</a>)</p>
  <p>Salmi, R., Hammerschmidt, K., &amp; Doran‐Sheehy, D. M. (2013). Western gorilla vocal repertoire and contextual use of vocalizations. Ethology, 119(10), 831-847. <a href="https://doi.org/10.1111/eth.12122" rel="nofollow noreferrer">https://doi.org/10.1111/eth.12122</a> (<a href="https://www.researchgate.net/profile/Roberta-Salmi/publication/254256957_Western_Gorilla_Vocal_Repertoire_and_Contextual_Use_of_Vocalizations/links/5baa614992851ca9ed25cd80/Western-Gorilla-Vocal-Repertoire-and-Contextual-Use-of-Vocalizations.pdf" rel="nofollow noreferrer">PDF</a>)</p>
  
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Answers.Text: Thanks Marc, this could be an hypothesis, however the papers do not make a relationship between these air sacs and the acoustics of chest beats, don't they?
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Body: <p>I am surprised by the relatively high pitch of Gorilla chest drumming (listen <a href="https://youtu.be/lc-2EbIEmwM" rel="nofollow noreferrer">here)</a>, which peak frequency <a href="https://www.nature.com/articles/s41598-021-86261-8#data-availability" rel="nofollow noreferrer">ranges between 600-700 Hz</a>. Actually, they sound like human-cheek drumming (listen <a href="https://youtu.be/aYN4sT0Z-UE" rel="nofollow noreferrer">here</a>)!!</p>
  <p>When a human beats their own chest, this sounds far lower pitch than gorilla (but far quieter I agree...). While human-cheek drumming peak frequency is related to those of vocal track formants, <a href="https://www.nature.com/articles/s41598-021-86261-8#data-availability" rel="nofollow noreferrer">gorilla chest beating peak frequency is related to body size (Wright et al 2021)</a>,
  <a href="https://i.sstatic.net/6CpXV.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/6CpXV.png" alt="enter image description here" /></a>
  but the exact involved resonators seem unknown according to them:</p>
  <blockquote>
  <p>Our measure of body size, back breadth, likely correlates with a range
  of morphological traits, including chest volume, pulmonary capacity
  and hand size. Therefore it is unclear which specific trait or traits
  are responsible for driving the inverse relationship between back
  breadth and peak frequency. Moreover, gorillas like other non- human
  primates possess laryngeal air sacs which are thought to act as
  resonators, enhancing acoustic signals4,11,24. Indeed, gorillas appear
  to use laryngeal air sacs during growling vocalizations which often
  accompany chest beating24. The volume of laryngeal air sacs is likely
  to be directly correlated with body size, at least within-species
  (which in orangutans (Pongo) can reach a massive 6 L38). Thus larger
  males are expected to have larger laryngeal air sacs than smaller
  males, further lowering the resonating non-vocal frequencies produced
  whilst chest beating. However, our knowledge of the size and function
  of laryngeal air sacs in primates and other taxa remains poor39.</p>
  </blockquote>
  <p>Anyone knows more about it here?</p>
  <p>Actually, the only reason why I'm asking this question is probably to be found in <a href="https://youtu.be/eojSvHhcNmo" rel="nofollow noreferrer">King-Kong low-pitch chest beat sound</a>, I'm sorry :-D.</p>
  
Tags: <fictional-sounds><mammals>
Title: Why are gorilla chest beats so high-pitched?
ThreadText: # Why are gorilla chest beats so high-pitched?
  
  (Asked by: username_0 on 2023-07-03)
  
  I am surprised by the relatively high pitch of Gorilla chest drumming (listen [here)](https://youtu.be/lc-2EbIEmwM), which peak frequency [ranges between 600-700 Hz](https://www.nature.com/articles/s41598-021-86261-8#data-availability). Actually, they sound like human-cheek drumming (listen [here](https://youtu.be/aYN4sT0Z-UE))!!
  
  When a human beats their own chest, this sounds far lower pitch than gorilla (but far quieter I agree...). While human-cheek drumming peak frequency is related to those of vocal track formants, [gorilla chest beating peak frequency is related to body size (Wright et al 2021)](https://www.nature.com/articles/s41598-021-86261-8#data-availability),
  [![enter image description here](https://i.sstatic.net/6CpXV.png)](https://i.sstatic.net/6CpXV.png)
  but the exact involved resonators seem unknown according to them:
  
  > Our measure of body size, back breadth, likely correlates with a range
  > of morphological traits, including chest volume, pulmonary capacity
  > and hand size. Therefore it is unclear which specific trait or traits
  > are responsible for driving the inverse relationship between back
  > breadth and peak frequency. Moreover, gorillas like other non- human
  > primates possess laryngeal air sacs which are thought to act as
  > resonators, enhancing acoustic signals4,11,24. Indeed, gorillas appear
  > to use laryngeal air sacs during growling vocalizations which often
  > accompany chest beating24. The volume of laryngeal air sacs is likely
  > to be directly correlated with body size, at least within-species
  > (which in orangutans (Pongo) can reach a massive 6 L38). Thus larger
  > males are expected to have larger laryngeal air sacs than smaller
  > males, further lowering the resonating non-vocal frequencies produced
  > whilst chest beating. However, our knowledge of the size and function
  > of laryngeal air sacs in primates and other taxa remains poor39.
  
  Anyone knows more about it here?
  
  Actually, the only reason why I'm asking this question is probably to be found in [King-Kong low-pitch chest beat sound](https://youtu.be/eojSvHhcNmo), I'm sorry :-D.
  
  **Tags:** fictional-sounds, mammals
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2024-11-11. Score: 2
  
  Gorillas have laryngeal air sacs that extend over the top of their chests.
  
  Nishimura, T., Mikami, A., Suzuki, J., & Matsuzawa, T. (2007). Development of the laryngeal air sac in chimpanzees. International Journal of Primatology, 28, 483-492. [https:/doi.org/10.1007/s10764-007-9127-7](https://https:/doi.org/10.1007/s10764-007-9127-7) ([PDF](https://www.researchgate.net/profile/Akichika-Mikami/publication/225148707_Development_of_the_Laryngeal_Air_Sac_in_Chimpanzees/links/5418f3de0cf25ebee98828e9/Development-of-the-Laryngeal-Air-Sac-in-Chimpanzees.pdf))
  
  Salmi, R., Hammerschmidt, K., & Doran‐Sheehy, D. M. (2013). Western gorilla vocal repertoire and contextual use of vocalizations. Ethology, 119(10), 831-847. <https://doi.org/10.1111/eth.12122> ([PDF](https://www.researchgate.net/profile/Roberta-Salmi/publication/254256957_Western_Gorilla_Vocal_Repertoire_and_Contextual_Use_of_Vocalizations/links/5baa614992851ca9ed25cd80/Western-Gorilla-Vocal-Repertoire-and-Contextual-Use-of-Vocalizations.pdf))
  
  > **Comments:**
  > **username_0**: Thanks Marc, this could be an hypothesis, however the papers do not make a relationship between these air sacs and the acoustics of chest beats, don't they?  
  
  ---
  
  