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Yakety Sacs: Laryngeal Air Sac Usage In Great Apes, Chelsea Trenbeath

Master of Science in Integrative Biology Theses

Except for humans, extant great apes have evolutionarily conserved lateral ventricular air sacs extending from laryngeal saccules. Humans are the only species of Hominidae that lack this anatomical feature attached to the primary vocal apparatus. As we are the only species that produces spoken language, this association has led to the hypothesis that the loss of lateral ventricular air sacs was necessary for the evolution of spoken language. However, why these sacs are conserved in all other hominids remains unclear. Computer modeling has indicated that air sacs may increase resonance properties, but there are no data from great apes indicating …