On: Tetrachromats: people who see colors invisible to ...

[zachrose]

Can dogs just not distinguish between colors that we can, or are they actually missing out on parts of our visual spectrum?

[A_Parr → zachrose]

Both. They can't differentiate between red/orange/yellow, can't differentiate greens from grays, but can see further into UV at the cost of not being able to see as deeply into red as you can.