These studies have a practical aspect. "If you understand how vocal folds are structured and what effects that structure has on vocal production, then it could help doctors make decisions on how to reconstruct damaged vocal fold tissue" in people such as cancer patients, singers, teachers, coaches and drill sergeants, he says.
Voices of Big Cats
The new study analyzed vocal folds from within the larynx, commonly known as the voice box. Larynges were excised from three lions and three tigers euthanized for humane reasons due to advanced disease at the Henry Doorly Zoo in Omaha. They ranged from 15 to 22.4 years old at death. The three lions were females. The tigers were female Sumatran and Bengal tigers and a male Amur (Siberian) tiger.
Vocalization is complex, and involves factors not included in the new study of vocal folds: how air is pushed from the lungs, how sound resonates in the vocal tract, how the tongue and jaw move, and movement of muscles and cartilage of the larynx.
The study included examinations of vocal fold tissue, which is soft connective tissue in the form of elastin, collagen, a lubricant known as hyaluronan, and fat.
Lions and tigers have large vocal folds: about 1 inch high from top to bottom, 1 inch thick side to side and 1.5 inches long front to back. They protrude from the larynx into the airway just above the trachea, forming a triangular shape on each side of the airway in most species but a squared shape in lions and tigers.
Scientists already knew lions and tigers have significant fat within their vocal folds. The new study showed that in big cats, this fat is located deep within the vocal fold ligament, and helps give the folds their flattened, square shape.
That shape "makes it easier for the tissue to respond to the passing airflow," al
|Contact: Lee Siegel|
University of Utah