Can Rats See Red Light?

Rats have two types of color cones in their retinas, one for green and one for blue ultraviolet light. Their color vision is very similar to humans. As a result, they probably perceive red, green, and blue hues. However, they can’t distinguish certain shades of gray. Rats’ color vision is not quite so perfect, but they can certainly distinguish certain shades of red.

Rats are not naturally red-light blind, but they do absorb red light through their rod-dominated retinas, which support form vision. The current study aims to investigate whether rodents can see red light under photopic and scotopic conditions. Red lights are commonly used in husbandry experiments, as they mimic the darkness phase.

Rats can see red light in scotopic conditions. However, when exposed to high-intensity red light, they are more sensitive to the light. This difference is particularly noticeable when the light is brighter than 500 nm. As a result, a rat’s photopic spectral sensitivity function peaks between 361 and 500 nm.

However, this heightened sensitivity to red light is not a cause for concern. Because rats’ eyesight is geared toward detecting brightness, they can distinguish between colors in different wavelength ranges. This is important for detecting objects. However, rats’ vision is not suited for distinguishing red and green. The resulting color perception is blurry and unsaturated.