Mice are highly vocal creatures, but the question of whether they truly “scream” when caught is complex and depends heavily on the sound frequency. Their communication spans a broad spectrum, extending from the human-audible range into the ultrasonic range. Distress calls are often pitched outside the range of human hearing, making the perception of a loud shriek unlikely for most people. The sound a person might hear is typically a high-pitched squeak, but the full extent of a mouse’s distress is usually silent to us.
The Audible Sounds of Mouse Distress
While a high-decibel, human-like scream is not part of a mouse’s repertoire, they produce distinct, loud sounds when physically trapped or in pain. These audible vocalizations fall into the sonic range, generally below 20 kilohertz (kHz), which is the typical cutoff for adult human hearing. The sounds heard by people are usually described as high-pitched squeaks, peeps, or chattering noises. These vocalizations are a direct response to acute stress, such as being restrained or injured. Scientific studies sometimes classify these as “squeaks” (below 20 kHz) or “mid-frequency vocalizations” (MFVs), which often range between 15 and 20 kHz.
Communication Beyond Human Hearing
The majority of a mouse’s acoustic communication, including alarm and distress signals, occurs in the ultrasonic frequency range. These sounds, known as Ultrasonic Vocalizations (USVs), occur at frequencies above 20 kHz, typically ranging from 30 kHz up to 120 kHz. Since most adult humans cannot perceive this high-frequency range, the mouse’s most intense communication is effectively silent to us. The use of USVs is an evolved strategy, likely allowing for localized communication that is not easily intercepted by many common predators. In high-stress situations, adult mice emit lower-frequency USVs, sometimes in the 26 to 36 kHz range, which are associated with aversive or negative states.
The Role of Vocalization in Warning and Defense
The different types of vocalizations produced by a mouse in distress serve specific biological functions related to survival and social interaction. Audible squeaks and aversive USVs function as alarm signals with dual purposes. One primary role is as a direct defense mechanism intended to startle or deter an immediate threat. The loud, high-pitched audible squeak acts as a sudden warning, potentially causing a momentary hesitation in a predator. This brief pause provides the mouse with a small window for escape.
Social Alarm Calls
The ultrasonic distress calls also function as social alarm calls, particularly for other mice in the vicinity. For mouse pups, USVs, typically in the 40–60 kHz range, are cries for help that prompt the mother to search and retrieve them. In adults, these calls contribute to the overall acoustic environment, signaling danger or stress to nearby conspecifics.