What sounds do rats fear? - briefly
Rats are startled by high‑frequency ultrasonic noises and sudden loud sounds such as predator vocalizations, metal clatter, or alarms. These noises trigger innate escape responses and elevated stress hormones.
What sounds do rats fear? - in detail
Rats possess a highly developed auditory system that detects sounds associated with danger. Fear‑inducing stimuli fall into several distinct categories, each triggering specific physiological and behavioral responses.
• Predator vocalizations – calls from owls, hawks and feral cats occupy the 2‑5 kHz range and contain rapid amplitude fluctuations. Exposure elicits freezing, increased heart rate and escape attempts.
• Ultrasonic alarm calls – conspecific distress signals are emitted around 20‑50 kHz. Playback provokes heightened vigilance, rapid locomotion and release of stress hormones.
• Sudden broadband noises – abrupt sounds exceeding 80 dB, such as metal clatter or a dropped object, generate startle reflexes, elevated corticosterone levels and avoidance of the source.
• Low‑frequency vibrations – ground‑borne rumblings below 200 Hz, produced by heavy footsteps or machinery, are interpreted as approaching large organisms and cause retreat behavior.
• Human speech with aggressive intonation – tones featuring sharp pitch rises and high‑frequency components (approximately 3‑6 kHz) can be perceived as threatening, leading to reduced foraging and increased alertness.
Experimental data demonstrate that rats show the strongest aversive reactions to sounds that combine high intensity, rapid onset and frequencies overlapping their hearing peak (approximately 8‑32 kHz). Neural recordings reveal activation of the amygdala and auditory cortex during exposure, confirming the link between auditory cues and fear circuitry.