(in many male frogs) a loose fold of skin on each side of the mouth, which can be inflated to produce sound.
- ‘Calling site was noted by counting males in calling posture (or with an inflated vocal sac) near each pool.’
- ‘There are dads who incubate their babies in their mouths, their vocal sacs, and in pouches.’
- ‘This frog thumps its gular pouch against the soft soil where it lies and rapidly inflates its vocal sac.’
- ‘Sex was determined from the presence or absence of vocal sacs and thumb pads.’
- ‘In Rhinoderma darwinii, males retain the tadpoles in their vocal sacs until the young metamorphose.’