張一帆

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.

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.

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.

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.

Humans may have the advantage in color vision，but dogs definitely have us beat in the realm of night vision. This is because dog's eyes have more light-gathering power than ours，Neitz says.

A dog's retina is largely composed of cells called rods，which can sense light，even in very low-light conditions，says Sypniewski.

人類的眼睛通過視網(wǎng)膜的視錐細胞感知顏色，狗也是如此，但兩者的視錐細胞并不完全相同。

科羅拉多州立大學教授、獸醫(yī)學博士、獸醫(yī)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?！?/p>

俄克拉何馬州立大學小型動物醫(yī)學教授、獸醫(yī)臨床醫(yī)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。

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、研究員杰伊·內(nèi)茨博士稱，“狗看不見紅色或綠色，但能看到所有藍黃色調(diào)的顏色。”

人類在色覺方面可能有優(yōu)勢，但狗的夜視能力肯定比人類強。內(nèi)茨說，這是因為狗的眼睛比人的眼睛更能聚光。

西普尼夫斯基說，狗的視網(wǎng)膜主要由視桿細胞組成，即使在光線很弱的情況下，視桿細胞也能感知光線。