How do frogs produce their croaking sounds?

Frogs produce their croaking sounds using a specialized vocal sac located under their throat. When a frog inhales, it fills its vocal sac with air, and then it forces the air back through its larynx, causing the vocal cords to vibrate and produce sound. The croak is amplified by the vocal sac, which acts as a resonating chamber. Frogs croak to attract mates, defend their territory, and communicate with other frogs. The pitch and pattern of the croak can vary by species and environmental factors, such as temperature and humidity.