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Often symbolizing wisdom, intelligence and mystery, owls are stoic creatures of the night. They soar through the sky, swiftly capture prey, and perch high in the trees. Owls can even rotate their heads nearly 270 degrees! Why? Today, we answer that question with help from National Geographic and ScienceDaily.
Keep your head still and look forward. As a human, you are able to see what is directly in front of you and some of what is to the left and to the right of you. This is called your peripheral vision. Without moving your head, your eyes can follow objects up, down and side-to-side.
Owls can’t do this. Because they have fixed eye sockets, they must move their heads in order to see their surroundings. A wide range of motion is critical for survival as it helps them avoid predators and detect prey.
But, how do they do it?
In 2013, researchers from Johns Hopkins unveiled this mystery. They wanted to understand why sudden movements to a human’s head and neck can be life threatening but not for an owl. They found four biological differences between a human’s and an owl’s anatomy that give the bird uninterrupted blood flow and greater arterial flexibility.
“The first anatomical variation they discovered was in the owl neck, where one of the major arteries feeding the brain passes through bony holes in the vertebrae,” according to ScienceDaily. “The hollow cavities were approximately 10 times larger in diameter than the vertebral artery traveling through it. The researchers say the extra space … creates a set of cushioning air pockets that allow the artery to move around when twisted.”
The researchers also noticed that the vertebral artery enters the neck at the owl's 12th cervical vertebrae, rather than the 14th like other birds. This allows for even for more vessel room and slack.
Unlike a human whose arteries tend to get smaller and smaller as they branch out, the owl’s blood vessels at the base of the head get larger and larger so that blood reservoirs form. This allows the owl to “meet the energy needs of their large brains and eyes, while they rotate their heads.”
And even if one blood vessel is blocked during rotation, blood is still able to flow to the brain due to the connection between the carotid and vertebral arteries.
So even though owls do not have peripheral vision, they’re able to safely scan an area by rotating their head and not interrupt blood flow to their brain—an important feature for the symbol of wisdom.
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