Figure 1.

Illustration of vocalization strategies of mammals in‐air and underwater. (i) Pinnipeds in‐air vocalization through the larynx; (ii) Pinnipeds underwater vocalization potentially via expansion of the tracheal membrane; (iii) Terrestrial species’ in‐air production via perpendicular vocal folds in the larynx; (iv) Mysticete underwater production of sound using parallel vocal folds in the larynx; (v) Odontocete underwater production via phonic lips and the melon.Silhouettes by Tracy Heath, Steven Traver, and Chris Huh were downloaded from http://phylopic.org.