We all know eagles soaring way up in the sky see much better than us, but why?
Birds of prey, like the eagle, can spot and track a rabbit’s movements from a mile above while they themselves are soaring through the air. But how do they do it?
“Mine” by Dr. Moore
Well, our human eye sees with a retinal membrane that lines the back of the eye. It’s loaded with special photoreceptor cells called rods and cones. These cells take the visual data and change it into information our brains can use. Humans have about 200,000 of these photoreceptors per square millimeter, while the eagle’s retina has over 1,000,000 per square millimeter! That gives the eagle roughly four to six times better visual acuity than humans.
Both humans and eagles also have a special small portion of the retina called the fovea, and its jam packed with just cones to give super clarity to things we see straight ahead of us. The fovea is indented a bit, giving even more surface area to pack in more cones. But the eagle’s fovea is indented even more, sort of like a deep pouch. So the number of these special cones is way more than in the human fovea. So this anatomical resolving power of an eagle’s deep fovea is how he sees so sharply at such amazing distances.
I guess you could compare our vision and the eagle’s to that of a computer having 4MB of RAM versus 512MB’s. Not literally of course. But it does give you an idea of the vast difference between human vision and an eagle’s vision. Yes, the raptor’s eye design is more efficient, but his brain is itty bitty. Maybe that’s why we read blogs and they make nests with twigs.
Don’t get me wrong! We may have bigger brain power, but we have much to learn from the world around us.