Can Dogs See Color? Learn All About a Dog’s Color Spectrum
狗可以看到颜色吗？了解小狗眼中的色彩世界
Isabel Roy
伊莎贝尔·罗伊
If you’re lucky enough to live with a pooch or two, you’ve probably spent a decent amount of time trying to figure out dog behavior. But trying to see things from your dog’s point of view brings up another question: Can dogs see color? You may know if dogs can see in the dark, but many people believe that when it comes to distinguishing green grass from a blue sky, dogs are totally color-blind and can only see in black and white. However, as science has advanced and we’ve learned more about the other animals who share our planet, researchers think they’ve finally found out exactly what your dog can see when they stare at you. It turns out that dogs don’t see only in black and white after all.
如果你很幸运养了一两只宠物狗，你很可能花了大量时间想弄明白它的行为。但是如果你试图从小狗的视角看事物，你可能会产生一个新疑问——狗可以看到颜色吗？你可能知道狗是否在晚上能看见，但是很多人认为狗是“色盲”，无法辨认绿草和蓝天的颜色，坚信在它们眼里世界是黑白的。但是随着科学发展，我们越来越了解与我们同住地球上的各种动物。研究人员称，他们发现当狗盯着你看的时候，究竟能看到什么。事实证明狗能看到的不止黑白两色。
Are dogs color blind?
狗是色盲吗？
The answer is a little bit complicated. “Dogs can see color,” says Zay Satchu, DVM, Chief Veterinary Officer of Bond Vet. “Both humans and animals have different types of cells in the back of their eyeballs—called rods and cones—that help them see. Rods detect motion and help with nighttime vision, and cones help with color and detail in what we see. Humans have three kinds of cones, meaning we see color and detail very well, while dogs have two kinds, meaning they can still pick up on colors but probably can’t differentiate between forest and lime green as easily.”
这个问题回答起来有些复杂。邦德兽医公司首席兽医官、临床兽医学博士Zay Satchu说：“人类和动物眼球后面都有视杆细胞和视锥细胞这两种类型的细胞，来帮助他们视物辨色。视杆细胞的功能是感知物体运动，主管夜晚视力；视锥细胞的功能则是感知颜色以及辨别视觉细节。人类有三种视锥细胞，也就是说我们对颜色和视觉细节的感知十分灵敏，相比之下，狗只有两种视锥细胞，也就是说它们也可以看到颜色但是可能无法轻易辨别森林绿和黄绿色。”
However, by human standards, dogs are definitely color blind. According to Britannica, a common type of color blindness in humans is known as dichromacy, meaning the eye has only two working cones, as opposed to the regular trichromacy, or three working cones. Humans with dichromacy might see the world in something close to the dog color spectrum. Have you ever wondered what colors cats can see?
但是，以人类的标准来看，狗无疑患有“色盲症”。根据大英百科全书介绍，人类有一种常见的色盲类型称作二色性色盲，也就是说患有二色性色盲的人的眼球上只有两种功能正常的视锥细胞，而视觉功能正常者的眼球上一般有三种视锥细胞。患有二色性色盲的人类看到的世界可能接近于狗眼中的色彩世界。那你是否想过猫能看到哪些颜色？
What colors can dogs see?
狗能看到哪些颜色？
They may not be able to see the whole rainbow, but it seems that your pooch can see a couple of colors really well: blue and yellow. “Most dogs can’t see much of red or green at all,” explains Dr. Satchu. While they can see some colors, the nuances of those colors (like the difference between plum and violet) are probably lost on dogs. Maybe that’s why dogs love bright yellow tennis balls so much: They can see them clearly against the gray or brown that dogs see when they look at something green, like your freshly mowed lawn. That’s something to keep in mind when you’re picking out your dog’s next puzzle toy. If you want to see the world through your dog’s eyes, download the Dog Vision app and take a look.
它们可能看不到彩虹全部的颜色，但是你的狗对蓝色和黄色这两种颜色感知十分敏锐。Dr. Satchub表示大部分狗无法感知到红色和绿色。即使它们能看到一些颜色，但是它们对一些颜色（比如紫红色和紫罗兰色）的分辨能力极弱。可能这也可以解释为什么狗对明黄色的网球爱不释手。在狗狗眼里绿色的事物，比如新打理的草坪，都是灰色和棕色的，明黄色的网球在一片灰棕色中便非常亮眼。下次给你的狗挑选玩具的时候一定要记住这一点。如果你想了解你的狗狗眼中的世界，可以下载 Dog Vision 这款应用程序进行小小的尝试。
However, the dog color spectrum includes colors that humans can’t see, says Dr. Satchu. “The other ‘color’ that exists that humans can’t see but dogs can is ultraviolet, meaning ‘beyond violet.’ We’re still evaluating the true purpose of this vision, but we think it has to do with the ability to pick up on the kinds of substances that contain ultraviolet light, like urine and blood, that help with tracking out in the wild,” she explains. When you think about how ultraviolet light would contrast with the grey-brown background of the forest, it makes sense that your dog’s vision is adapted to help them hunt. After all, we all know that dogs have superpowers.
但是Dr. Satchu也表示狗能看到的色谱范围有些是人类看不到的。她说：“另一种人类看不到但狗能看到的颜色就是‘紫外线’。我们也正在研究这种视觉能力的真正用途，但是我们认为这可能和捕捉含有紫外线的各种物体的本领相关，比如说尿液和血液，这种本领有助于狗在野外进行追踪活动。”你想想在葱郁的森林中，狗眼中的世界是灰棕色的，这种情况下，紫外线的光会和背景色形成强烈反差，因为可以说狗的视力范围有助于帮助它们捕食。毕竟，我们都知道狗有超能力。
What does a dog’s vision look like?
狗的视力怎么样呢？
Now we know that dogs see a limited spectrum of colors, but how far can they see? According to PetMD, dogs have visual acuity of around 20/75. Normal human vision is considered to be 20/20, so dogs have to be 20 feet away to see an object as clearly as a human can see it from 75 feet. Most dogs have pretty blurry vision—if they were human, they’d need glasses to see faraway objects. However, Labrador Retrievers have better eyesight than most dogs. It’s closer to 20/20, which is why they’re often used as service dogs (here’s why you can’t pet a service dog).
现在我们知道狗可以看到色谱中有限的一部分颜色，但是它们的视力如何呢？根据PetMD，狗的视敏度约为20/75。正常人类的视敏度为20/20，因此人站在23米远的地方可以看到某个物体，狗则需要站在6米远的地方。大部分狗视力模糊，如果以人类的标准来看，它们需要佩戴眼镜才可以看清远处的物体。然而，拉布拉多犬的视力要优于大部分犬类，它的视力接近20/20，这也是为什么拉布拉多犬经常被用作服务犬（也可以说明为什么规定个人不能将服务犬作为宠物）。
Dogs may have fewer cones for seeing color than humans do, but they have many more rods in their retina than we do, which makes them much better at seeing movement—essential for a hunting animal. In fact, dogs can see moving objects much more clearly than they can stationary objects, and their motion sensitivity is up to 10-20 times greater than ours. That’s how they see a squirrel in the park before you do! It’s just one of the things your dog wishes you knew.
由于狗的视锥细胞种类比人类少，它们能看到的颜色便也少于人类能看到的颜色，但是它们视网膜上分布的视杆细胞要多于人类，因此它们对运动的感知能力更强，这种感知能力对狩猎性动物来讲至关重要。其实，狗对动态事物的感知要强于对静态事物的感知，它们对移动事物的侦视能力比人类强10到20倍。这也是为什么它们能在你之前看到公园里的松鼠！这也只是你的狗希望你了解的事情中的某一件罢了！
【VOCABULARY】
1. pooch n. 狗
2. rod n. 视杆细胞
3. cone n. 视锥细胞
4. lime green 黄绿色
5. Britannica 《大英百科全书》
6. dichromacy n. 二色性色盲
7. trichromacy n. 三色视觉
8. spectrum n. 光谱
9. ultraviolet adj. 紫外线的
10. urine n. 尿
11. blurry adj. 模糊的
12. retina n. 视网膜
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