Males of the South American species incubate their young in their vocal sacs. The London Zoo recently established a breeding ...

and can amplify the sound with a vocal sac that makes sound resonate. Frogs mostly call to attract mates, but they can also make sounds to warn others about their territory, or to express distress ...

Constant exposure to the sounds of a busy road can impact a male European tree frog’s stress levels, immune system, and vocal sac coloration, scientists show. To study the effects of road noise on ...