Si tu veux lire cet article en fran莽ais,
听Dogs are听听whereas humans are听. That means that our eyes contain 3 different types of cone cells, each of which are responsible for detecting a unique colour (for a description of both rods and cones, click听here). That鈥檚 why every colour you can think of is a combination of the 3 primary colours.
But dogs only have , and instead of them sensing red, blue or yellow, they鈥檙e to violet and yellow-green. This means that dogs have less sensitivity in their green, yellow and red detection than humans. But conversely, humans have less sensitivity in their blue and purple detection than dogs.
And ? Well they are a bit of a mystery. We know that they have at least , one tuned to violet and one to green. But there have been studies the showed evidence of a third type of cone cell, one sensitive to light at (greenish-blue to us). Other studies have this finding, and yet others have found evidence of a cone cell sensitive at (red to us). Currently, it鈥檚 believed they have vision similar to , called photopic trichromatic vision. In essence, they likely see similar colours to us, but not quite in the same clarity or saturation.
There鈥檚 is growing evidence that dogs and cats can听, something no human can do!
Cats鈥� and dogs鈥� vision systems evolved to help them hunt. They鈥檙e better at seeing movement than still objects; they see best in low light rather than bright; and they have larger visual fields (up to 270掳 compared to the 180掳 of humans!)
Cats and dogs also have evidence of their previous 听s, or third translucent eyelids, in the corners of their eyes. These would once have听allowed听them to maintain their sight on prey when hunting without their eyes drying out.
So when you throw a red ball into a green field, Rover sees a yellow ball being thrown into a white or gray field. Those colours just aren鈥檛 that different, so don鈥檛 be too surprised when he can鈥檛 find the ball that鈥檚 obvious to you!
