Night vision in cats.

Posted: July 31, 2011 in Animals, Random facts and WTFs

Cats (as well as many other nocturnal animals) have a very cool eye structure called tapetum lucidum, which is located behind photosensitive retina.

In humans, when the light hits retina, a very large portion of this light just goes through retina and gets “lost” (absorbed) by choroid.

In cats, however, this light gets reflected back by tapetum lucidum and hits retina for a second time, allowing a more efficient photoreception.

Such retinal illuminance gives cats night-vision abilities 5-8 times better than those of humans (and it also gives cats this spooky glowing-eyes effect).

By the way, it’s sort of similar to a human red-eye effect, which can be observed on some photos (it’s caused by pigments in the human choroid, which absorb everything but low-frequency light waves (red), which get reflected back to the camera and, thus, cause eyes to appear red).

Cats’ night vision is awesome, indeed. But nothing is perfect.

We, humans, have an extremely good colour vision (in comparison to nocturnal animals, who are mostly dichromats, meaning that they able to perceive only two primary colours). Our visual acuity is also supreme (cats are not capable of focusing on things in the same way we do because of their tapetum lucidum…. even if they had an intelligence close to ours, their vision would be too blurry to allow them to read anything :) ).

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