Rats utilize a wide range of sounds to interact with their environment and each other. Their vocal repertoire is divided into two main categories: sounds within the range of human hearing and those pitched too high for us to detect. Understanding these noises is helpful for identifying a potential pest issue or better understanding the behavior of a pet rat. The majority of their communication involves rapid, high-frequency signals.
Vocalizations Audible to Humans
The noises rats produce that are audible to humans—typically below 20 kilohertz (kHz)—are often signals of distress, warning, or interaction. The most common audible sound is a squeak, which can vary significantly in pitch and length depending on the context. A sudden, high-pitched, and loud squeak generally indicates fear, pain, or surprise, acting as an alarm or distress signal to others nearby.
Softer, lower-pitched squeaks or chirps are sometimes heard during social interactions like play or grooming. These sounds can signify a more content or playful state, though they are often still at the upper limit of human hearing. Hissing is another vocalization that signals aggression or defense, usually occurring when a rat feels threatened or is engaged in a dominance struggle. A rat may also produce a loud, high-pitched shriek or scream when experiencing extreme pain, though this is uncommon.
The difference in pitch and intensity is a direct clue to the rat’s emotional state. Higher-pitched sounds often communicate positive excitement or sudden shock, while lower tones indicate anger or fear. Many vocalizations pet owners describe as “chirping” or “singing” are actually on the cusp of the human hearing range. Any unusual audible vocalizations, especially wet-sounding chirps or clicks, can also be a sign of a respiratory issue.
Physical Sounds and Movement
The sounds rats make through their actions and movement are often the first indication of their presence in a home or building. One of the most distinctive physical noises is gnawing, produced as rats chew on hard materials like wood, plastic, or wiring to maintain the length of their incisor teeth. This chewing sound is a persistent, scraping noise that often leads to structural damage or electrical fires.
Scratching and scuttling noises are also frequently heard, especially at night when rats are most active, as they move within walls, ceilings, or attics. These sounds result from their claws dragging across surfaces as they search for food or nesting material. Tail drumming is a physical sound where a rat rapidly beats its tail on a surface, which is thought to be a territorial display or a warning signal.
Rats also produce a sound called bruxing, which is the act of grinding their incisor teeth together, creating a rhythmic chattering or rasping noise. This sound is often compared to a cat’s purr because it typically signals contentment and relaxation in a pet rat, sometimes accompanied by a bulging of the eyes known as “boggling.” Bruxing keeps their teeth filed down, but it can also be a sign of stress or pain if observed in a tense animal.
Communication Using Ultrasound
The majority of rat communication occurs in the ultrasonic range, meaning the sounds are above 20 kHz and inaudible to human ears without specialized equipment. These ultrasonic vocalizations (USVs) are their primary means of social interaction and signaling emotions. Researchers have broadly categorized USVs into two main frequency groups, each with a distinct emotional meaning.
Vocalizations around 50 kHz are associated with a positive emotional state, indicating pleasure, anticipation, or social approach. These high-frequency calls are emitted during mating, play, and when anticipating a reward. These calls tend to be short in duration and are often frequency-modulated, meaning the pitch rapidly shifts.
In contrast, calls centered around 22 kHz are associated with a negative emotional state, serving as alarm or distress signals. These lower-frequency USVs are emitted in response to aversive circumstances, including pain, the presence of a predator, or social isolation. The 22 kHz calls are typically longer than the positive 50 kHz calls, sometimes lasting up to 3.5 seconds, and contain less frequency modulation.