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House Sparrow - Passer domesticus This is Bob. He sleeps on my deck every night. Oddly, he sleeps with his eyes open. He is completely asleep in this picture! I know this because I climbed up on my railing and put my hand right in front of him, and he didn&#039;t even twitch.  Nothing makes him stir - not me or my flash.  I am always quiet near him though so I don&#039;t wake him.<br />
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I was curious why he sleeps with his eyes open, and discovered that this behavior is called Unihemispheric Slow-Wave Sleep. It means that an animal can sleep with one half of the brain, while the other half remains alert. This is in contrast to normal sleep where both eyes are shut and both halves of the brain show reduced consciousness.  Geotagged,House sparrow,Passer domesticus,Summer,Unihemispheric slow-wave sleep,United States,bird,house sparrow,passer,sleeping bird,sparrow Click/tap to enlarge Promoted

House Sparrow - Passer domesticus

This is Bob. He sleeps on my deck every night. Oddly, he sleeps with his eyes open. He is completely asleep in this picture! I know this because I climbed up on my railing and put my hand right in front of him, and he didn't even twitch. Nothing makes him stir - not me or my flash. I am always quiet near him though so I don't wake him.

I was curious why he sleeps with his eyes open, and discovered that this behavior is called Unihemispheric Slow-Wave Sleep. It means that an animal can sleep with one half of the brain, while the other half remains alert. This is in contrast to normal sleep where both eyes are shut and both halves of the brain show reduced consciousness.

    comments (5)

  1. Cool! I once came across sleeping birds also with their eyes open in Madagascar. Before that moment, I had never really considered how birds sleep. Have to say though that this half-alert stage did not really impress me, it was more like not alert at all :)

    Sleep well, Bob. You will need the energy for Becky.
    Posted 3 years ago
    1. It scared me the first time I saw him. I was trying to take pictures of moths and I felt like he was watching me, like a total creeper. And, yeah, the so called "half alert" notion seems bogus. I had my hand mere centimeters from his face and he didn't move at all.

      Bob gets a good night sleep each night on my deck, so Becky is a lucky girl.
      Posted 3 years ago
      1. So cute! Posted 3 years ago
  2. This is such a nice little story! Yes, birds are blessed with this ability. I have also seen them in some animals underwater, for example, several fishes when we encounter them in night dives. I don't know if in their case the mechanism is different than for birds but they definitely sleep without any membrane helping them to close the eyes.
    As for the birds, the most amazing example is migratory birds that sleep with one half of their brain while still flying to their destination, for example the albatrosses do that. Isn't amazing?
    https://www.sciencealert.com/scientists-have-just-seen-birds-sleep-while-flying-for-the-first-time-ever
    Posted 3 years ago
    1. That is definitely amazing! Posted 3 years ago

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The house sparrow is a bird of the sparrow family Passeridae, found in most parts of the world. A small bird, it has a typical length of 16 cm and a weight of 24–39.5 g. Females and young birds are coloured pale brown and grey, and males have brighter black, white, and brown markings.

Similar species: Passerines
Species identified by Christine Young
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By Christine Young

All rights reserved
Uploaded Aug 4, 2018. Captured Aug 3, 2018 22:53 in 5 East St, New Milford, CT 06776, USA.
  • Canon EOS 80D
  • f/10.0
  • 1/64s
  • ISO400
  • 100mm