An owl can turn its head up to 270 degrees from the front without harming itself. This remarkable ability allows owls to rotate their necks much farther than humans, who can only turn their heads about 90 degrees to each side (180 degrees total). Owls have special adaptations in their bones, muscles, and blood vessels that allow this extreme rotation without cutting off blood flow or damaging nerves. While some studies suggest owls might be anatomically capable of a full 360-degree head turn, they typically do not perform a complete circle due to other anatomical constraints such as nerve safety. So, commonly, owls rotate their heads about three-quarters of a full circle or 270 degrees to keep watch of their surroundings.
