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Dogs have less visual sharpness comparison to humans. That is to say, they need to be four times closer than us to an object to perceive its details. However, in the night, dogs can see perfectly, they can even get along well in the most darkest ambience. They can see as well as if there was sun light.
There’s a popular legend that says that cats are the owners of the night. But nevertheless, they share together with their dog friends an excelent night vision thanks to the Tapetum Lucidum that both animals have in their eyes. This weave layer located in the back of the eyeball (and that would be translated from Latin as something similar to “bright tapestry”) is the responsible for amplifying the light that is received. This tissue is one of the reasons why the eyes of both breeds shine in the dark: the effect is caused, simply, by the light reflected in the bottom of the eye, in the Tapetum Lucidum.
Thats why in the night we see clear or greeny eyes in our pet, and if we take a picture of him with the flash on he’ll always show up with really bright eyes. This characteristic of the dog is a direct inheritance from his ancestor the wolf, a nocturnal hunter with impeccable night vision.