Buccal Expansion during Hissing in the Puff Adder, Bitis arietans
Videoradiographic analyses were made of hissing in puff adders (Bitis arietans). During the hiss the larynx remains relatively stationary immediately adjacent to the internal nares. The exhalatory portion of the hiss is characterized by a distinct expansion of the caudal buccal cavity, including a depression of the hyoid and divergence of the cornua. This buccal expansion is hypothesized to be an epiphenomenon of intraoral pressure generated by the exhalatory airstream of the hiss.Abstract
Lateral images of a 128 cm SVL Bitis arietans during the onset (A) and termination (B) of the exhalatory phase of the defensive hiss. Approximately two seconds separates these two images. Note the distinct expansion of the buccal floor in (B)
Frontal images of a 128 cm SVL Bitis arietans during the onset (A) and during (B) the exhalatory phase of the defensive hiss. Note the expansion of the buccal floor, and the depression and divergence of the hyoid (arrow)