Is an Eagle’s Vision Better than a Human’s? It is estimated that an eagle’s visual acuity is at least four to eight times better than that of a human.Ī soaring eagle can spot its unsuspecting prey up to 2 miles (3.2 km) away. Like the brim of a hat, the ridge offers support, protection, and even some sun protection. One characteristic of eagles that really stands out is their supraorbital ridge, which is the bony projection above their eyes that gives these birds a “fierce” appearance.įierce look of a bald eagle due to the supraorbital ridge. They must turn their entire head to gaze around and can swivel their heads nearly 270 degrees. The eyeball is so big and so snugly fitted that the eagle can hardly turn it inside the orbital socket. Some researchers believe that the space between the two foveae of an eagle, which resembles a long, narrow ribbon, is actually a third fovea! What are Some Physical Characteristics of Eagle Eyes? Eagle eyes are so big they take up nearly one-third of the head. This dense concentration of cone cells provides eagles with the best vision of any vertebrate species. In comparison to an eagle’s central fovea, which has over a million cone cells per square millimeter, a human’s fovea has roughly 200,000 cone cells per square millimeter. The vitreous in the deep fovea may act as a third lens, increasing magnification to the optic system.
However, the precise function of each fovea is uncertain. According to researchers, their eyes can operate like telephoto lenses by magnifying objects in the center of their fields of vision thanks to their deep fovea. From Duan et al, 2013.Īccording to the anatomy of the foveae, the deep fovea (nasal fovea) has the highest acuity, especially useful for viewing objects from a long distance. Line of sight (LOS) for deep fovea vs shallow fovea. The deep fovea’s (nasal fovea) line of sight is forward and approximately 45 degrees to the right or left of the head axis, while the shallow fovea’s line of sight is forward but approximately 15 degrees to the right or left of the head axis. In contrast to the deep convex pit found in hawks and eagles, the human fovea is like a little shell or bowl. Raptors, including falcons, hawks, and eagles, have two retinal regions specialized for acute vision in each eye: the deep fovea and the shallow fovea. This remarkable visual acuity is made possible by the tubular shape of the eye, a huge pupil, retinas with cones, and a significantly deeper fovea, a structure in the back of the eye that is rich in cones. Imagine being able to spot a pizza from 2 miles away! And pizzas don’t normally hide camouflaged under bushes! Why Do Eagles Have Such Amazing Visual Acuity? An eagle can see an animal the size of a rabbit about 2 miles (3.2 km) away.Ī rabbit is roughly the size of a medium pizza. Eagles have evolved the ability to quickly change the shape of their cornea and lens to focus on both near and far objects at high speed.Eagles have a 340-degree field of vision with peripheral eyesight superior to humans.An eagle must turn its head to look to the side and can swivel its head nearly 270 degrees.Eagle eyes fill their entire sockets and are fixed in place.Sometimes a bird’s eyes are heavier than its entire brain! Eagle eyes are huge the eyes of a 10-pound (4.5-kg) eagle may be as large as those of a human weighing 200 pounds (90.7 kg).An eagle’s eye has two focal points, or fovea, one pointed forward and the other to the side.Eagle eyes have one million cone cells per mm2 compared to 200,000 per mm2 for human eyes.Eagles have a remarkable 20/5 or 20/4 visual acuity, which means that they can see things from 20 feet away that we humans would only see from 5 feet away.Eagles and hawks have the best vision of any vertebrate species.When an eagle swoops down on its prey at 100 mph, the muscles in its eyes continuously adapt the curvature of the eyeballs to maintain a crisp focus and precise depth perception. Eagle eyes have over one million cone cells per mm2 compared to human eyes with 200,000 cone cells per mm2. The remarkable vision of an eagle is the result of key adaptations in its eyes. A soaring eagle can spot a rabbit from 2 miles (3.2 km) away. It is four to eight times better than ours. Eagles and other birds of prey have the best visual acuity of any group of animals.
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