How do rats see and hear? - briefly
Rats possess dichromatic vision, sensitive to ultraviolet and green light, with limited visual acuity and a strong dependence on motion cues. Their auditory system detects frequencies up to roughly 80 kHz, allowing precise perception of ultrasonic vocalizations and environmental sounds.
How do rats see and hear? - in detail
Rats rely on a visual system adapted to low‑light environments. Their retinas contain a high proportion of rods—approximately 85 % of photoreceptors—providing acute sensitivity to dim illumination but limited color discrimination. The few cones present are tuned to short wavelengths, allowing detection of ultraviolet light. Visual acuity is modest; spatial resolution averages 1 cycle/degree, far below that of primates. Nevertheless, rats can detect motion and contrast efficiently, using retinal ganglion cells that emphasize changes in luminance. The optic nerve projects to the superior colliculus and visual cortex, where motion cues guide navigation and predator avoidance.
Auditory perception in rats is characterized by a broad frequency range and exceptional sensitivity to ultrasonic sounds. The cochlea exhibits a basal region responsive to frequencies up to 80 kHz, enabling detection of vocalizations and environmental cues beyond human hearing. Outer hair cells amplify low‑intensity sounds, while inner hair cells transduce mechanical vibrations into neural signals with high temporal precision. The auditory nerve conveys this information to the brainstem nuclei—cochlear nucleus, superior olivary complex—and onward to the auditory cortex, where frequency and amplitude modulation are decoded.
Key physiological features:
- Rod‑dominant retina: high scotopic sensitivity, limited color vision.
- Ultrasonic hearing: frequency detection up to 80 kHz, fine temporal resolution.
- Auditory brainstem circuitry: rapid sound localization via interaural time and level differences.
- Visual‑auditory integration: superior colliculus combines motion cues from both modalities for orienting responses.
Behavioral studies show rats orient toward moving stimuli, discriminate between sound frequencies, and use ultrasonic vocalizations for social communication. These sensory adaptations support nocturnal foraging, predator detection, and complex social interactions.