My hypothesis is that most herbivores perceive the world differently from most carnivores. The former are watching for something sneaking up on them, the latter are trying to stalk a still prey.

Therefore, herbivores are looking for movement, and vision that is optimized to detect silhouettes will be most likely to detect movement. Also, herbivores need to be able to carry on with their activities while peripheral vision works on “autopilot.” It takes hours of grazing to satisfy their energy needs; they can’t be on the alert all day.

Carnivores, on the other hand, can spend those same hours in the stalk. They need to be able to detect an animal that is holding still and hiding. The carnivore needs to be able to see into cover and focus on details that give away the prey, even if the prey animal has detected him already.

These generalizations are deliberately vague, and I expect that many counter-examples exist.