Do Rats Have Good Eyesight?
WouterRats have a color vision that is comparable to humans, but not as accurate. They have two types of cones in their retinas – short “blue-UV” cones and long “green” cones. Rats’ blue cones peak at 359 nm, much shorter than human blue cones. This allows them to distinguish red and green from each other, but it also limits their vision to a narrow range.
The researchers used head-mounted cameras to examine rat vision. They found that rats do not align their eyes with each other during free movement, preventing stereopsis. But they do maintain a wide binocular overlap above their head, presumably to detect flying predators. This is a good sign for rats’ eyesight, but they need to be studied further.
Although rats do not have good eyesight, they have other useful traits that enable them to survive in their environment. They have a good sense of smell, which helps them find food and navigate. Their sense of smell also allows them to recognize one another. This helps them avoid predators. They can also see food at a distance, a trait that is highly desirable for survival.
Rats have a depth of focus that is about 20/600, much smaller than humans’. This means they have excellent depth perception. The depth of focus is a measurement of how far an object is in focus for an unaccommodated eye. In humans, it ranges from 2.3 meters to infinity, while rats’ depth of focus is just seven centimeters. This difference between humans and rats may be a result of the small size of the rat eye. Rats also have poor acuity, which limits their depth of focus. Further, humans can perceive blurriness after a change of 1/3 diopters, while rats require 14 diopters to be aware of blurring.
