What does it mean when wildlife biologists say that “an eagle can see a rabbit in a field from miles away”? Does this imply that their vision is automatically more zoomed in? Do they have better than 20/20 vision, or is their vision simply clearer?

Question

What does it mean when wildlife biologists say that “an eagle can see a rabbit in a field from miles away”? Does this imply that their vision is automatically more zoomed in? Do they have better than 20/20 vision, or is their vision simply clearer?

In: Biology

Answer 1

Their vision is much, much better than 20/20. 20/20 means you can see at 20 feet what a normal person with clear visual acuity sees at 20 feet. (20/40 means you see at 20 what a normal eye sees at 40; 20/10 means you can see at 20 what a normal human eye sees at 10 feet – good for you.) Hawks and eagles are probably around 20/4 or 20/5, meaning they can see from 20 feet what a healthy human eye sees from 4 feet.

They’re not more zoomed in, they can just perceive and process many more details in their field of vision than we can.