The secret behind bird's superior vision over humans and all the other animals on the planet lies mostly in their extraordinary retina, which grows out of the brain during development, making it an official component of the central nervous system, according to a new study.
Researchers at the University of Hamburg have shown that a protein unique to avian retina contributes to visual acuity by helping eyes 'breathe'.
Birds spot their dinner from long distances and dive-bomb those moving targets at lightning speed. And then there are the owls, which operate nimbly on even the darkest nights to secure supper in swift swoops.
Some birds have ultraviolet sensitivity; others have infrared sensitivity. To boot, some birds can even see the Earth's magnetic field.
Indeed, the avian retina is far more complex in structure and composition than the human retina, and it contains many more photoreceptors-rod- and cone-shaped cells that detect light and color, respectively.
While researchers over the years have come to better understand much about the avian retina, many nagging questions remain.
For Thorsten Burmester's research team, the question was this: How does such a productive retina sustain itself when the avian eye has very few capillaries to deliver oxygen to it?
The team took a closer look at a protein that they discovered exists in large quantities in photoreceptor cells of the avian eye-and only of the avian eye. They named the protein globin E.
They used a number of techniques to characterize globin E and found that it is responsible for storing and delivering oxygen to the retina.
The study appeared in this week's Journal of Biological Chemistry.