Squirrels are known for loud vocalizations, often generalized as screams, barks, or aggressive chatter. These sharp noises are part of a communication system used to navigate their environment and social interactions. Squirrel calls serve the purposes of warning, defense, and signaling danger. These high-volume calls are typically categorized into three main contexts, each with a distinct function.
Signaling a Predator Threat
The most common loud vocalization is an alarm call directed at a perceived threat, such as a hawk, cat, or human. These sounds often begin with a short, sharp bark known as a “kuk,” which is frequently repeated in rapid succession to indicate immediate danger to nearby conspecifics. Researchers note that this series of calls may transition into a longer, more drawn-out, and rougher sound called a “quaa” if the threat remains or intensifies.
These alarm calls, often coupled with rapid tail flicking, serve a dual purpose. The sound warns other squirrels, allowing them time to seek cover or freeze in place. The loud vocalization also communicates to the predator that it has been detected, a strategy known as “perception advertisement.” A predator that knows it has been spotted may determine the pursuit is less worthwhile and abandon the hunt. The specific structure of the calls can even contain information about the type of threat, such as a “moan” associated with aerial predators.
Defending Territory and Resources
Loud vocalizations are also a central component of intraspecies conflict, occurring when a squirrel is disputing resources or territory with a rival squirrel. In this scenario, the loud sounds function as an aggressive display intended to establish dominance and avoid a costly physical fight. The vocalizations used here often include a harsh, aggressive chattering, which can be accompanied by the grinding of teeth.
For more solitary species, like the North American red squirrel, a specific vocalization known as a “rattle” is used to communicate territory ownership. Broadcasting this sound from a food cache or nesting site effectively deters rivals from intruding. This aggressive communication is paired with physical displays, such as posturing, chasing, and exaggerated tail twitching, to reinforce the threat. This combination of sound and visual display establishes boundaries over valuable items without requiring actual combat.
Distress, Injury, or Capture
The true “scream” in a squirrel’s repertoire is typically a high-pitched, panicked distress call that signals immediate and personal peril. This sound is a last-resort vocalization, usually emitted when the animal is severely injured, physically caught by a predator, or being aggressively handled. The sheer volume and intensity of this scream can be startling, with some nestling distress calls measured at approximately 72 decibels.
This piercing sound is meant to draw attention to the immediate danger. The shriek may momentarily startle an attacker, potentially allowing the squirrel a brief window to escape a fatal grip. The distress call may also alert other nearby animals, including larger predators, whose intervention could inadvertently disrupt the attack. This panicked scream is the most acoustically distinct from regular barks and chatters, representing the most extreme level of alarm a squirrel can express.