Laryngeal Sacs

protrusions of the mucosa of the larynx in some mammals, which act as resonators in voice production.

Paired laryngeal sacs are well developed in the anthropoid apes and are present in horses, asses, tapirs, and certain toothed whales. Besides paired laryngeal sacs, an unpaired sac is sometimes formed by a protrusion of the laryngeal wall between the thyroid and cricoid cartilages (for example, in martens, marmosets and tamarins, and some whalebone whales) or between the thyroid cartilage and the epiglottis (for example, in the reindeer, antelope, and the majority of apes). The unpaired laryngeal sac, together with the paired sacs, is especially well developed in howler monkeys, whose cry can be heard several kilometers away.