有不少人誤以為，狗狗的世界只有黑白兩色。實際上，狗狗可以看到藍色和黃色等顏色，雖然與人類相比它們的色覺非常有限。不過，與人類相比，狗狗的視覺也有一些優勢，比如它們在黑暗中能看得更清楚。你知道狗是如何區分顏色的嗎？一起來看看狗狗眼中的世界吧。
...狗的視覺與人類的視覺有何區別
Your eyes pick up color using a type of cell called cones in your retina. The same is true for dogs, though our cones aren’t exactly the same.
人類的眼睛通過視網膜的視錐細胞感知顏色，狗也是如此，但兩者的視錐細胞並不完全相同。
Humans have three types of cones, “which enables us to see different shades of red, blue-violet, and green,” says Alison Meindl, DVM, a veterinarian, and professor at Colorado State University.
科羅拉多州立大學教授、獸醫學博士、獸醫艾莉森·梅恩德稱，人類有三種視錐細胞，「因此我們能夠看到不同深淺的紅色、藍紫色和綠色。」
Dogs have two types of cones that pick up blue-violet and yellow shades, says Lara Sypniewski, DVM, a professor of small animal medicine at Oklahoma State University.
俄克拉何馬州立大學小型動物醫學教授、獸醫臨床醫生拉臘·西普尼夫斯基稱，狗有兩種視錐細胞，可以分辨藍紫色和黃色。
This means that dogs see in a similar way to humans who are red-green colorblind. “They don’t see red or green and they see everything in shades of blue and yellow,” says Jay Neitz, Phd, a researcher and professor of ophthalmology at the University of Washington.
這意味著狗的視覺與紅綠色盲的人相似。華盛頓大學眼科教授、研究員傑伊·內茨博士稱，「狗看不見紅色或綠色，但能看到所有藍黃色調的顏色。」
...Humans may have the advantage in color vision, but dogs definitely have us beat in the realm of night vision. This is because dogs’ eyes have more light-gathering power than ours, Neitz says.
人類在色覺方面可能有優勢，但狗的夜視能力肯定比人類強。內茨說，這是因為狗的眼睛比人的眼睛更聚光。
A dog’s retina is largely composed of cells called rods, which can sense light, even in very low-light conditions, says Sypniewski.
西普尼夫斯基說，狗的視網膜主要由視杆細胞組成，即使在光線很弱的情況下，視杆細胞也能感知光線。
...關於狗狗視力的冷知識
Dogs are especially good at sensing movement. “The increased number of rods in the dog’s retina also increases their ability to detect motion,” Sypniewski says. This ability can help them detect small prey like squirrels.
狗特別擅長感知運動。西普尼夫斯基說：「狗的視網膜中視杆細胞數量多，這使得它們觀察運動的能力更強。」這種能力可以幫助它們發現像松鼠等小獵物。
Dogs have a wider field of vision than humans. Dogs’ eyes are set slightly farther apart than humans’ eyes, so they can see further to the side in each direction.
狗的視野比人類更廣。狗比人的眼間距稍遠，因此它們可以在每個方向上看得更遠。
Dogs have blurrier long-distance vision than humans. A human with perfect vision has 20/20 vision, while dogs have 20/65 to 20/85. This means that “a dog must be at 20 ft. to read a letter that a human with 20/20 vision would be able to read at 65 or 85 ft.,” says Sypniewski.
狗的遠距離視力比人類更模糊。擁有完美視力的人類有20/20的視力，而狗有20/65至20/85的視力。這意味著「狗必須在20英尺（約合6米）處才能看見一個擁有20/20視力的人類在65或85英尺處能看到的字」。
...Dogs have trouble seeing things very close up. Dogs can see objects clearly if they’re at least 13 to 20 inches away from their eyes, “but if the object is closer, the image may be blurry,” Sypniewski says. Humans can see objects slightly closer — about 10 inches away from the eye.
狗很難近距離觀察事物。「當物體距離眼睛至少13到20英寸（約0.3到0.5米）遠時，狗狗能看清楚，」但如果物體更近，眼中的圖像可能就會模糊不清。人類可以看到更近的物體，大約到10英寸（0.25米）遠。
Dogs may recognize you by your shape and motion. “If your dog recognizes you from a distance, it is not because it can see the details of your face like a human would, but rather because of your shape or the way you move,” Neitz says.
狗可以通過身形和動作識人。內茨說：「如果你的狗能從遠處認出你，那不是因為它能像人類一樣看清楚你的臉，而是因為認出你的身形或移動方式。」
...來源：Insider
編輯：董靜
來源：中國日報網
