[deafpolygon]

It is theorized that they had vision like eagles or possibly exceeded that of eagles that enabled them to see prey at great distances. Then using their legs optimized for locomotion, they would chase them down.

It feels like most people mix the two things up: excellent vision and predatory response. An eagle can absolutely see a mouse hiding in the bushes, not moving. But a moving prey is what triggers their predatory response. Plausibly… they probably don’t attack a non-moving mouse because it could be a dead mouse.

Human vision evolved for different things. Our ancestors were tree-dwelling and optimized for depth perception, social cues and color acuity. So it’s just a different strategy.

[ETH_start]

I suspect that the movement is more than just a predatory response factor. It is also used as an indication that there is something to give attention to. The eagle may be able to see the motionless mouse if it focuses on it, but it doesn't know to focus on it unless it detects the motion to draw attention to that area of its visual field.