Can Owls Turn Their Heads 360 Degrees? How Far They Really Turn

How far can an owl turn its head?

Starting from looking straight ahead, an owl can swing its head around to face directly backward and keep going, for a total rotation of roughly 270 degrees. Humans, by comparison, can turn the head only about 70–90 degrees to each side.

An owl can also tilt its head sideways to extreme angles, sometimes until its face looks almost upside down. Owls bob, sway and tilt their heads when they study something, because viewing an object from slightly different positions helps them judge its distance.

Photos and videos sometimes seem to show an owl turning its head all the way around. What usually happens is that the owl turns its head as far as it goes in one direction, then whips it back the other way faster than the eye can follow, so it looks like a complete circle.

Why do owls need to turn their heads so far?

The answer lies in the owl’s eyes. Owl eyes are enormous for the size of the head and shaped more like short tubes than balls. This shape gives a large, bright image for seeing in low light (see can owls see in the dark?), but it leaves no room for the eyeball to rotate. A ring of small bones in the eye, called the sclerotic ring, holds each eye rigidly in place.

As a result, an owl cannot glance sideways the way people do. To look at anything that is not straight ahead, it must move its whole head. A very flexible neck makes up for the fixed eyes and lets the owl scan its surroundings while its body stays still.

Keeping still is a real advantage. A hunting owl perched on a branch can track a vole moving below, or check behind for danger, without shuffling its feet or ruffling its feathers and giving itself away.

How does an owl’s neck work?

Owls have 14 neck vertebrae, twice as many as humans and most other mammals, which have seven. Each joint contributes a small part of the total twist, so the rotation is spread along the whole neck instead of being forced through one or two joints.

The neck also has a single pivot point where the skull joins the spine. In owls, as in other birds, the skull rests on one rounded knob of bone (the occipital condyle), while mammals have two. A single contact point lets the head swivel more freely, a bit like a ball on a socket.

All this is hidden under a thick layer of feathers. An owl’s neck is longer than it looks; the round, compact outline of a perched owl is mostly fluff.

Why don’t owls cut off their blood supply?

Turning the head this far should be dangerous. In people, sudden, forceful twisting of the neck can tear or pinch the arteries that run through the neck bones and feed the brain. A 2013 study by researchers at Johns Hopkins University, published in the journal Science, investigated how owls avoid this. The team injected dye into the blood vessels of owls that had died of natural causes, including snowy, barred and great horned owls, and imaged them with scans and dissection.

They described several adaptations:

• Roomy bone tunnels. The vertebral arteries pass through holes in the neck vertebrae that are about ten times wider than the arteries themselves, leaving a cushion of space as the neck twists. In humans these holes are about the same size as the artery.
• Slack in the arteries. The vertebral arteries enter the neck bones higher up than in other birds, giving the vessels extra length and slack lower down.
• Blood reservoirs. Blood vessels at the base of the head can widen to hold a pool of blood, which may keep the brain and eyes supplied while the neck is turned.
• Cross-connections. Small linking vessels (anastomoses) join the main arteries of the neck, so blood can take another route if one path is squeezed.

Together these features let an owl twist its head quickly and repeatedly without starving its brain of blood.

Do all owls turn their heads the same amount?

The figure of about 270 degrees is widely quoted for owls in general, and both the great horned owl and the barn owl can turn their heads far enough to look directly behind them. Detailed measurements exist for only a few species, so small differences between owls are likely but not well documented.

What all owls share is the reason behind it: fixed, tube-shaped eyes and a hunting style that depends on staying motionless. Owls that hunt from perches, such as the great horned owl, spend much of the night quietly turning their heads to watch and listen in every direction.

Myths and facts

• Myth: owls can turn their heads in a full circle. They cannot. The limit is about 270 degrees.
• Myth: an owl’s head can come loose or “unscrew”. This is a playground joke, not biology. The head is attached by strong muscles and ligaments.
• Fact: owls turn their heads partly to hear. Many owls have ear openings at slightly different heights on each side of the head. Turning and tilting the head helps them pinpoint where a sound is coming from.
• Fact: young owls practice. Owlets bob and swing their heads in exaggerated movements as they learn to judge distances, which is one reason they look so comical.