Why do birds have eyes? That sounds like a silly question. Suppose you said, “So they can see,” you would be correct. But that’s not the only purpose for a bird’s eyes.
Bird’s eyes also serve to cool the bird’s body. People sweat, dogs pant, but birds have another cooling system. Flying is a high-energy activity, and it can raise a bird’s body temperature so much that the heat could damage its central nervous system. A bird’s eyes are designed to eliminate this problem.
As the wind rushes past the eyes of a flying bird, it evaporates water from the surface. This evaporation cools the blood in the nearby veins. The cooler blood prevents the temperature of the bird’s brain from going too high. Scientists proved this by putting hoods over the heads of some birds. If the eyes were covered, the brain temperature rose dramatically. If the eyes were uncovered, the brain temperature stayed constant.
You might be surprised to know what animal has the most sophisticated visual system. Its eyes have at least twice as many types of color receptors compared to human eyes. They have three focal points while human eyes have only one. This animal can see both ultraviolet and infrared light, which our eyes cannot do. It has six polarization channels in each eye with high polarization sensitivity and hyperspectral imaging. What is the animal with this incredible visual system? It’s the mantis shrimp–a marine crustacean of the order Stomatopoda.
Researchers studying this animal’s eye say that it not only surpasses the sensitivity of our own visual system, but also captures more visual information, uses less power, and takes up less space than the most sophisticated state-of-the-art cameras. Scientists at the University of Illinois have developed a color-polarization camera based on the mantis shrimp’s visual system. The camera can aid in the early detection of cancer.
Mantis shrimps communicate using polarized light which cannot be detected by predators. They polarize the light by sending it across a reflector rather than the conventional method of sending the light through a lens. Researchers are copying this method of the mantis shrimp to develop a single chip, low-power, high-resolution color-polarization camera. The National Science Foundation and the Air Force Office of Scientific Research are sponsoring the project. The mantis-copied camera concept has great potential for a variety of applications.