how do humans know that some animals see in black and white or see more colours than us?

Answer 1

We can tell by the cones and rods in their eyes. Humans have both but if you only have one of the other you can tell what colors the animal sees.

Rod cells are highly sensitive to light allowing them to respond in dim light and dark conditions, however, they cannot detect color. These are the cells which allow humans and other animals to see by moonlight, or with very little available light (as in a dark room). This is why the darker conditions become, the less color objects seem to have. Cone cells, conversely, need high light intensities to respond and have high visual acuity. Different cone cells respond to different wavelengths of light, which allows an organism to see color.

Answer 2

there are certain cells in the eye that see colors, other see black and white. They have studied animals eyes and found different levels of these cells that lead them to think that some animals see in only black and white. new research lately has shown this may not be the case and that animals do see colors, just in a different way.

Answer 3

Well i'm a human and I read about it in books[not ordinary books but what students read] and I read that some animals cannot see colour that humans can. If I line up some balls in front of my dog. Green--blue--yellow--brown---black and I told hime to pick one up..which one would he pick up? I also read that the house fly with all those lenses in its eyes can only see in black and white images.

Answer 4

You train an animal to recognize the difference between a + and a o, say by giving food if the + is touched. Then you make signs in which the + and o differ from the background by a very small amount (for more colors) or only look different in color but look the same if color blind (like medium red + and medium green background which is easy for us to see.)
No cutting of eyeballs, no counting of pigments, no torture, no long discussions.

Answer 5

Humans have a lot of rods in their eyes, which are good for color vision and detail. Animals have a lot of cones, which dont do color but are more sensitive to light. When the lights go out you rely on your cones as your rods cant help you and thats why in dim light things go black and white.

Answer 6

On the retina of the eye rods are sensitive to black and white shades (intensity) whereas cones are sensitive to colours (frequency). I guess they look at ratios in animals retinas to determine how they see the world.

Answer 7

Scientists examine there eyes, human eyes have a lot of rods in them compared to animal eyes that have cones

Answer 8

I suppose they have done tests, eg throwing different coloured balls or something and seeing if the animals can distinguish between them.

Answer 9

We know by studying the wavelength absorption of the opsins produced in retinal cells.

Answer 10

Because we've examined their retinal contents and found that some animals have only the right types of cells to make a dichromatic image, where as we (unless you are colorblind), have enough to make trichromatic vision.