Why do mantis shrimps and birds (including predatory birds) have the ability to see so many colors? What purpose does it serve?

Question

Based on info I got by searching this sub, color vision exists to help forage for ripe fruit, while less cones/more rods help hunt/track movement etc – so it seems counter-intuitive for these predators to have such vast color vision.

Thank you

In: 1

Answer 1

How do people know how/what an animal can see in the 1st place? Like do an autopsy on the eyeball?