Why are animals colourblind?

Question

I have a dog and is he colourblind?

Answer 1

Dogs, in certain repsects, are wolf puppies that didn't grow up normally.  Wolves prefer to be active from dusk till dawn, and their pronounced sense of smell helps them fulfill this.  In such circumstances, given the darkness, the ability to distinguish colours would be rather pointless.

Your dog is colour blind for reasons of descent.

Answer 2

animals may not need to see in colour, or to see colours as we do. no oint in them having useless facilities.

it may be that those seeing no colour hve sharper vision - in the way black/white photos seem sharper/clear & they are easier to identify objects, it seems..

Answer 3

Its just how they are.

You were born with eyes. Thats just how you are.

Answer 4

Not all animals are colorblind. Most birds and reptiles can see color pretty well--birds actually have far better color vision than humans--mammals are kind of oddballs for being the other way around, with the majority having poor color vision. This is because you can only stuff so much sensitivity into one eyeball, so creatures with good night vision tend to have poor color vision, and vice-versa. Dogs fall into the first category, humans into the latter.

Dogs actually can see in color, though, just not nearly as well as we can: green, yellow, orange and brown all appear to be the same, blue-green appears as gray, and purple and blue are indistinguishable from one another. Red is either perceived as gray or black. This is why, to a wolf, deer with brown fur blend in so well against a green backdrop: the wolf can't tell green and brown apart.

Answer 5

We are animals and are not, generally speaking, 'colourblind'.

Different animals have different abilities to detect various parts of the electromagnetic spectrum. The range of wavelengths (=colours) which the human eye can detect can be seen in a rainbow, with the red end being of longer wavelength, the violet end of shorter wavelength. The electromagnetic spectrum extends indefinitely beyond both ends of the range to which our eyes are sensitive, lengthening to infra-red (which we can detect, not with our eyes but with heat sensors in our skin) and on to radio wavelengths, shortening to ultra-violet, x-rays, gamma rays and so on).

Through natural selection, animals will tend to evolve those visual abilities which are an advantage to them. Thus, to predators which hunt at night, sensitivity to low levels of light, regardless of wavelength (i.e. colour), seems more important than being able to discriminate among different wavelengths (i.e. see in colour).

Our own eyes actually have two types of photosensitive receptor - rods and cones. Cones can discriminate among different wavelengths of light and thus allow us to see in colour. Rods can't discriminate among different wavelengths, but are much more sensitive than cones. Notice how colours fade in low light levels - as night falls, for example.

Nocturnal predators (most members of the cat family, many of the dog family) will tend to have more rods, less cones. They will be better able to see than us in low light levels, but will be less sensitive to colour.

Some snakes have receptors that allow them to see in infra-red, in addition to their 'normal' eyes. This allows them to hunt warm-blooded prey (birds, mammals) in what would appear complete dark to us.

Some insects have eyes (incidentally, of very different construction from ours) sensitive to ultra-violet. This allows them to more easily locate certain ultra-violet-reflecting flowers. No doubt some pretty boring-looking flowers to us are actually beacons of psychedelia to bumble bees. Flowers, of course, represent a food source to pollinating insects. It seems the construction of the insect eye also makes it more sensitive to movement than the vertebrate eye, but this is nothing to do with colour.

I'm sorry, but I don't know about your dog in particular, but I see other answers to help.

You could always try to test your dog by offering it meals dyed with various (harmless) food dyes and see what happens! Green bones or purple?