I thought dogs, like most land predators, evolved green receptors first to detect movement in foliage, so shouldn't they see green better than this?

Their 2 sets of cones are apparently most sensitive to blue and yellow wavelengths vs our RGB.

https://www.britannica.com/story/are-dogs-really-color-blind

Well Seymour, you are an odd queer fellow, but I must say, you steam a good gay ham.

Gay ham, my favorite!

Seymour on the Atari 2600

Is this what color blind people see? Can someone confirm?

This is why they can lose sight of tennis balls on a lawn. Green and yellow look very similar to them. Give your dogs blue balls!

I have an app on my phone (called "CVSimulator") that represents types of colorblindness. I’ve shown it to people who are actually red/green colorblind and got confirmation from them that it’s pretty accurate.

Red/green colorblindness in humans can be either protanope or deuteranope. I’m not sure which one dogs would have (if someone is more knowledgeable on this, please chime in!) However, this is how my app interprets this image. The top is protanope, the bottom is deuteranope:

So it's a little off, but some of the colors are correct.

Evolutionarily, most mammals are color blind. Old world primates duplicated one corn and changed it a bit so we have three. Some lost one of them and so they are color blind. Since this is on the Y chromosome, it's much more common in males. Other vertebrates have 4 cones that are much more evenly distributed but early mammals were nocturnal so there was no need in color vision.

This doesn't answer which kind of human color blindness is closer to what most mammals see but it's not too different either way. Thanks!