why don’t dogs see color?

Question: why don't dogs see color?
- Keywords:
  colour,
  dog,
  sight
Asked by game45day to Souvik, Sabine, Maria, Armin on 21 Nov 2019.
- Maria McNamara answered on 21 Nov 2019:
  
  Dogs do see colour. They are not completely colour blind. They can see blues and yellows well, but red, pink, orange and purple all look grey to them.

Question: why don't dogs see color?