Eyes

[saucy potato]

How has it been determined that dogs (and other animals) are colour blind?

[ASPA]

Originally posted by saucy potato:
How has it been determined that dogs (and other animals) are colour blind?
By whom has this been determined. Not me. Could be, could be.

[DougC]

- - - Super Bonus Points Question, relating to another thread: if human albinos usually suffer vision problems, do animal albinos also have vision problems? - MC

[TBone2]

This is not a shot at the super bonus point question, but....

I recall reading several articles not so long ago to the effect that white-tailed deer, long assumed to be color-blind, actually are not. I believe the researchers that so concluded actually wired the brains of live deer and measured their reactions to visual exposures to different colors.

Gee, I shoulda been a scientist.....



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I don't know why fortune smiles on some and lets the rest go free...

T

[NothingMan]

small hijack . . .

TBone -

If your post is true, then I cannot help but laugh hardily at those hunters wearing bright orange. Isn't it ironic ?

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I'll be in the back slapping the big nosed rasta man.

[foolsguinea]

20th century urban myth--like "Babies only smile 'cos they have gas."

That said, there is a reason other mammals might not see the same colors we see in the same objects, and which could have led to the premature conclusion that they are colorblind.

Perceived color is a function of response to amounts & wavelengths of light by 4 (well, 4 in humans) different types of retinal cells (rods, red cones, green cones, & blue cones). If an animal's range of say, "green" response is different from ours, they will see different colors than we do in the same mess of light reflecting off an object. If they're "colorblind" by our standards, we're possibly "colorblind" by theirs as well.

Also, some species may have two or four cone types instead of three, no rods, only rods, or rods that read further into the infra-red.
Has any study of retinal cells shed any light on such variations? I read in Omni (?) once that dogs have two cone types: "[dog] blue" and "[dog] yellow." But knowing Omni, I take this cun grano salis.

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"In my nightmares I am chased by algorithms"--crewman Celes, ST:V

[L. G. Butts, Ph.D.]

Cecil wrote about this one:

http://www.straightdope.com/classics/a2_004.html

[foolsguinea]

AARG
"cum grano salis."
with a grain of salt.

oy....

[L. G. Butts, Ph.D.]

Cecil wrote about this one:

http://www.straightdope.com/classics/a2_004.html

[saucy potato]

Hmm... I suppose I should have said "assuming" that animals are colourblind.

Thank you, though.

[AWB]

Researchers showed various colored sheets of paper to dogs. They then asked the dogs what color they saw. To light colors, they said, "Ruff". To dark colors, they said, "Woof." To medium colors, they gave a "rrrWoof", indicating that they saw shades of gray.

Small dogs only answered, "yip," indicating that they are blind. Exception: chihuahuas kept saying "Chalupas."

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Wrong thinking is punished, right thinking is just as swiftly rewarded. You'll find it an effective combination.

[handy]

'hunters wearing bright orange...' hey, thats so that other hunters don't shoot them.

If you take red & green & they are the same *value* they look exactly a like in black & white. believe it or not.

[foolsguinea]

OK.
Now I've read Cecil's column--guess Omni was right.

Anyway, per Cecil's column,either cats are exceptionally dense, a proposition Cecil has no trouble buying, or else they just don't give a hoot about color. I'll second the opinion that cats may be exceptionally dense. At least, some cats can be. Could they be dense enough not to care about the color--visible to them--of a paper in an experiment designed to test their color sense? Hoo yeah, probably--if only 'cos they'd have no trust in the superior intelligence of humans, nor would they see any link between a wrapping's color and edibility of what's inside. 1500 tries to learn to look in the colored one first? Ha! That surprised me at first, then I remembered what cats I have known were like. Yes, we humans can be stupid--dangerously stupid--on a huge scale, but the stubborn denseness of cats reaches proportions we cannot comprehend.

Or maybe the researchers messed up somehow, which is my real opinion.

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"In my nightmares I am chased by algorithms"--crewman Celes, ST:V