Vocal sac

Vocal sacs are blind or balloon-like Hautausstülpungen of the oral cavity floor of the frogs and toads ( Anura ), which serve the males during the mating season as a resonance amplifier for their vocalizations (especially mating calls to attract females ). Your elastic wall consists of an inner mucosal layer, an at rest position more or less wrinkled skin and in between a ballooning of the floor of mouth muscle called muscle subhyoideus. In a quasi- closed system from the oral cavity, larynx and lung, the articulation takes place during flow through the larynx, the vocal cords are vibrated.

Mostly it is a single fillet constant ( subgulare ) vocal sac, which can inflate the animal very voluminous. Local examples are European Tree Frog, Natterjack Toad and Toad. In some American tree frogs occur subgulare sound bubbles with indicated two-part ( bilobater ) to paired expression. In the males of the water frogs are among the paired mouth, pendant vocal sacs, which are turned inward when not in use.

Some amphibians lack a vocal sac, others only have internal vocal sacs - their calls are much quieter, such as in the common toad and the grass frog. In general, these are so-called " tradition spawners " (k- strategists ), which always return to the same breeding waters, so that the partner determination over long distances by means of acoustic signals plays a lesser role. Interior sound bubbles are less bloated and are not marked in the rest position by skin folds - in contrast to species with external throat vocal sac.