Is it true that rats are blind? - briefly
Rats are not blind; they have functional eyes that detect light and motion, although their visual acuity is lower than that of many other mammals.
Is it true that rats are blind? - in detail
Rats possess functional eyes and are not devoid of sight. Their retinas contain rods and cones, enabling detection of light, motion, and color, though visual acuity is limited compared to primates. Typical rat visual acuity ranges from 0.5 to 1 cycle per degree, sufficient for navigating tunnels and recognizing objects at close range.
The predominance of rod cells gives rats heightened sensitivity in dim environments, supporting their nocturnal lifestyle. Cone distribution is sparse, resulting in reduced color discrimination; rats can differentiate between certain wavelengths but lack the full color spectrum of humans.
Depth perception arises from the lateral placement of the eyes, creating a wide field of view (~300°) with a modest overlap for binocular vision. This arrangement favors peripheral detection of predators and obstacles rather than precise stereoscopic analysis.
Behavioral studies show rats rely heavily on whisker (vibrissal) input and olfactory cues, supplementing visual information. Experiments using maze navigation demonstrate that vision contributes to task performance, especially when tactile or olfactory cues are minimized.
In summary, rats are sighted mammals with adaptations for low‑light conditions, limited resolution, and a visual system that complements other sensory modalities rather than serving as the primary means of perception.