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How Owls Twist Their Heads Almost 360 Degrees

In an Exorcist-style display of flexibility, owls can rotate their necks a maximum of 270 degrees without breaking blood vessels or tearing tendons.

To the untrained eye, it looks like a case of movie magic, but scientists at Johns Hopkins University School of Medicine now have data to explain the eerie skill that has baffled birders for years. (Check out National Geographic’s backyard bird identifier.)

Whereas people and other animals can simply move their eyes to follow an object or use peripheral vision to scan a room, owls must turn their heads for the same effect. These birds have fixed eye sockets, which means their eyeballs can’t rotate, forcing them to stretch their necks—a seemingly supernatural feat.

“In the case of birds, their systems are designed to handle that amount of movement,” said Eric Forsman, a wildlife biologist for the U.S. Forest Service, who was not part of the study.

“The tissue, the blood vessels are designed to flex—things don’t just snap.”

Turning Heads

Owls are more flexible than humans because a bird’s head is only connected by one socket pivot. People have two, which limits our ability to twist, Forsman added. Owls also have multiple vertebrae, the small bones that make up the neck and spine, helping them achieve a wide range of motion.

Yet, even with these skeletal advantages, a bird’s body shouldn’t be able to withstand such extreme levels of movement. In people, a spinning head would cause all kinds of internal bleeding and breakage.

For the new research, the Johns Hopkins team obtained 12 dead birds from educational centers and created 3-D images of the animals’ blood vessels and bones. The scientists also injected the carcasses with dye and liquified red plastic to preserve their arteries before dissection, according to a summary of their research on the U.S. National Science Foundation website.

The team discovered owls have backup arteries, which offer a fresh supply of nutrients when blood vessels get closed off by rapid turning. Their arteries also swell to collect any excess blood created in the process.

Eerie Ability Not Unique

It’s a powerful adaptive trait, Forsman said, but it’s not unique. Plenty of birds have a similar ability to look behind them. Red-tailed hawks, for example, are almost as flexible as their nocturnal cousins.

“There are lots of advantages to being able to look over your shoulder and see something coming—if you’re trying to avoid predators or detect prey,” he said. (Watch a video of an owl hunting prey.)

Owls might not be distinctive within the animal kingdom, but they do have the corner on Hollywood horror flicks. With their bulbous eyes and haunting calls, these birds can swivel their way from one thriller to the next.

The head-turning study won first place in the Posters category of the 2012 International Science & Engineering Visualization Challenge.

Comments

  1. Pres
    United States
    March 19, 8:57 pm

    Way cool!

  2. Daniel babare
    Nigeria
    January 6, 4:12 pm

    Wow i taut al diz were jst film tricks nt knwin dey were real

  3. siyabonga
    south africa
    December 10, 2013, 1:12 am

    nice research bro this is a very good mathematical explanation especially for rotation in the foundation phase keep it up guys

  4. Priscilla lornam Akagbo
    Ghana
    July 30, 2013, 8:44 pm

    Very helpful info, I’ve always wondered how they do it. I think its amazing and certainly unique. God is Amazing. :D

  5. RAJ KUMAR
    INDIA
    July 20, 2013, 10:09 am

    is there any animal with same feature.

  6. RAJ KUMAR
    INDIA, MOHALI
    July 20, 2013, 10:08 am

    is there any other bird with same feature of rotation.
    what about any other animal reg. rotation

  7. hade soelaeman
    Indonesia
    April 9, 2013, 7:51 pm

    Cool!

  8. kathleen hilman
    Wyoming, USA
    February 14, 2013, 1:04 am

    Fascinating! I have degenerative disc disease in my neck and what I would give to have just 1/4th the rotation abilities of the owl…wow!

  9. nateino
    earth
    February 11, 2013, 8:25 pm

    coolstorybro tell it again

  10. Shivani
    London
    February 10, 2013, 1:29 pm

    i have an assumption that the back-up arteries close up if the head is at it’s correct position, and as they say, the arteries are only in use when there is a close-up in the main vessels due to rotation. Therefore the rotated head must end up in a position which gives room for the back-up arteries to open up and vice verse.

  11. putra k.
    Indonesia
    February 10, 2013, 10:27 am

    o Hoo Hoo Hoo Ho… Who cooks for youu.. who cooks foor yoo .. who hoo..

    cute pic!!!

  12. Sasha
    Vancouver, Canada
    February 9, 2013, 12:27 pm

    Hey Janet, frm Australia…..its almost 360 degrees cuz its only 90 degrees less than 270!!!!! Not tht much!!!
    Sasha

  13. Sasha
    Vancouver, Canada
    February 9, 2013, 12:25 pm

    thts sooooo cul………….how do they do it????? its soooooo incredible!!

  14. Serena
    Toronto, Canada
    February 9, 2013, 12:23 pm

    WOW…nvr knew such things cud happen!!

  15. jesse
    corona ca
    February 9, 2013, 10:27 am

    How does this relate to the Indians belief in Owls accompanying spirits into the after life?

  16. Tanamon Somchana
    Lumnarai, Lop Buri Thailand
    February 9, 2013, 6:32 am

    In Thailand, many people were fear the owls because they like the ghost.

  17. GiGi
    USA
    February 9, 2013, 3:42 am

    I was always wondering how could Owls turn their neck like that. Now, I know ! Such a great animal full of wisdom.

  18. Mr Nosh B. Cooper
    Pune,Maharashtra, India
    February 8, 2013, 11:51 pm

    Appreciate your thorough description with Sketches of the Owls
    twisting their Heads almost 360 Degree. Worth reading

  19. Lovish Garlani
    Garli, Himachal Pradesh, India
    February 8, 2013, 8:41 pm

    Is there is any other organism with fixed eye socket. Why owls don’t able to see during day time ? Is it true?Is it due to their fixed eye socket?

  20. nikhil kumar rai
    delhi
    February 8, 2013, 1:44 pm

    Good but still i want to know what happen to the backup arteries after they get their head back to normal position… Do they still work…. And if these arteries don’t work then how they survive

  21. Edwin
    Mumbai , India
    February 8, 2013, 1:29 pm

    the picture is not clear at all even when i zoom in.

  22. elfigo moya
    albuquerque
    February 8, 2013, 1:17 pm

    If Owls cannot move their eyes, then it makes sense that they can rotate their neck 270 degrees. This absolutely is an adaptive trait. Natural selection has most definitely worked in the Owls favor. Only the strong survive, right? This article was a little dull, though. I will definitely do more research on this as should the people who wrote this article.

  23. Rodman M. Papros
    February 8, 2013, 4:12 am

    Honestly, I did not know owls are incapable of rotating their eyeballs. haha . . . cooooool!

  24. Janet Elson
    Australia
    February 7, 2013, 8:28 pm

    Impressive, but 270 degrees is not ‘almost 360 degrees’ is it ? :)

  25. Mariana Almeida
    Portugal
    February 7, 2013, 7:11 pm

    Amazing… =) For us, it’s fascinanting. For them, it’s “Evolution, evolution”…

  26. Brett McPoyle
    Australia
    February 7, 2013, 12:50 am

    Brilliant, I was hOWLING to find out about this one.

  27. christopher
    georgia
    February 6, 2013, 9:17 pm

    cool stuff