The development of colour vision in animals

[Catherine]

I had forgotten about that post. You did it while I was in Edmonton because I mentioned the dog sleeping with me. I don't get too many chances to sleep with a dog.

Dogs see more at the ultra violet end of the spectrum. I wonder now what the significance of that is. Why would ultra violet sight help dogs survive? Things develop because they help us survive. 

I think the world dogs see must be more vibrant than the one we see. They must get some important clues about the environment from the UV end of the light spectrum. Certain things glow under UV light. Dogs would see those things. Maybe it helps them to track things. If they can see a trace because of the UV vision, then they can use their sense of smell to track it.

Reptiles see more in the infra red spectrum. Snakes sense heat and can judge the size of something by its heat signature. That would matter to them because so many of them are nocturnal. They also don't need to really need to see details. They just need to know size and location of things around them.