The functions of laryngeal air sacs in primates: a new hypothesis.

The Joy of Sacs

This paper investigates an idea that was put forward (and hinted at in Fitch, 2000) by Tecumseh Fitch at the Cradle of Language conference in Stellenbosch, South Africa. The idea is that air sacs may have played an important role in early hominid vocalizations. Many other primates have air sacs, notably chimpanzees, gorillas and orangutans. It is therefore likely that our latest common ancestor...

On the Relationship between the Air Sacs Loss in the Genus Homo

In a series of works, different models have shed light on the acoustic properties of air sacs, an organ located in the laryngeal region that is present in all great apes with the exception of humans. These works have shown how the loss of air sacs expands the number of possible digits but not the amount of signals per se. The number of signals in human language increased when the codifying prop...

Sisters of the sinuses: cetacean air sacs.

This overview assesses some distinguishing features of the cetacean (whale, dolphin, porpoise) air sac system that may relate to the anatomy and function of the paranasal sinuses in terrestrial mammals. The cetacean respiratory tract has been modified through evolution to accommodate living in water. Lack of paranasal sinuses in modern cetaceans may be a diving adaptation. Bone-enclosed air cha...

The acoustic role of supralaryngeal air sacs

This paper investigates the acoustic effect of supralaryngeal air sacs on the range of sounds that a given vocal tract can generate. Humans do not have supralaryngeal air sacs, whereas apes (chimpanzees, orangutans and gorillas) do. It has also been found that the anatomy of the hyoid bone of Neanderthals (the Kebara hyoid) is consistent with the absence of air sacs, while that of Australopithe...

Re-dating the Loss of Laryngeal Air Sacs in Homo Sapiens