To Humans, Eagle Eyes Are Superpowered
Eagles have 20/5 or 20/4 vision in good viewing conditions, and can see four to five times farther than the average human. They also have a more vivid perception of colors, and the ability to see ultraviolet light. The latter power comes in handy when they're tracking prey-some small animals leave urine that reflects UV light.
from Earth Unplugged
Key Facts In This Video
Due to the shape of their retinas, cats see a more muted world than humans. (0:31)
Tarsiers have the largest eyes in proportion to body size of any mammal. (2:12)
Some species of birds of prey can spot their prey from 3 kilometers (1.9 mi) away. (4:05)