Why do small animals usually produce higher-frequency sounds than large animals?

In the study of animal behavior and biology, the relationship between an animal's size and the frequency of the sounds it produces or hears is largely dictated by physical constraints.

It is a common misconception that sound frequency is determined solely by an animal's intent; rather, it is heavily influenced by the mass and size of the anatomical structures involved in sound production and reception. Because large masses involve significant resistance when moved at high frequencies, the size and mass of these moving parts—such as the vocal cords in the larynx or the components of the inner ear—limit the range of frequencies an animal can effectively generate or perceive.1

Smaller animals possess smaller, less massive structures that can vibrate more rapidly, allowing them to produce and detect higher-frequency sounds. Conversely, larger animals are physically constrained by the inertia of their larger auditory and vocal apparatuses, which are better suited for lower-frequency vibrations. This is why, for example, elephants have a lower upper-frequency limit for hearing compared to smaller mammals like bats or rodents.12