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Physics

Vocal Sac Resonance and Acoustic Amplification in Anuran Amphibians

Quick fact

A bullfrog's vocal sac can resonate at the same frequency as its laryngeal sound source, amplifying the call up to 30 decibels—roughly making a whisper as loud as a busy city street.

Why this is interesting

Have you ever wondered how a tiny frog can produce a call so loud it can be heard from a kilometer away? The secret lies not in sheer muscle power, but in a remarkable inflatable balloon of skin—the vocal sac.