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How Well Do Dogs See At Night?
Science Daily ^ | 11-8-2007 | University of Wisconsin - Madison.

Posted on 11/08/2007 7:09:03 PM PST by blam

How Well Do Dogs See At Night?

ScienceDaily (Nov. 9, 2007) — A lot better than we do, says Paul Miller, clinical professor of comparative ophthalmology at University of Wisconsin-Madison.

Dogs have good night vision, due in large part to the tapetum, a mirror-like structure which reflects light, giving the retina a second chance to register light that has entered the eye. This is also what makes dogs eyes glow at night. The dog is holding a toy in her mouth. (Credit: Michele Hogan)

“Dogs have evolved to see well in both bright and dim light, whereas humans do best in bright light. No one is quite sure how much better a dog sees in dim light, but I would suspect that dogs are not quite as good as cats,” which can see in light that’s six times dimmer than our lower limit. Dogs, he says, “can probably see in light five times dimmer than a human can see in.”

Dogs have many adaptations for low-light vision, Miller says. A larger pupil lets in more light. The center of the retina has more of the light-sensitive cells (rods), which work better in dim light than the color-detecting cones. The light-sensitive compounds in the retina respond to lower light levels. And the lens is located closer to the retina, making the image on the retina brighter.

But the canine’s biggest advantage is called the tapetum. This mirror-like structure in the back of the eye reflects light, giving the retina a second chance to register light that has entered the eye. “Although the tapetum improves vision in dim light, it also scatters some light, degrading the dog’s vision from the 20:20 that you and I normally see to about 20:80,” Miller says.

The tapetum also causes dog eyes to glow at night.

Adapted from materials provided by University of Wisconsin - Madison.


TOPICS: News/Current Events
KEYWORDS: doggieping; dogs; night; see
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1 posted on 11/08/2007 7:09:04 PM PST by blam
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To: blam
Then how do we explain Hillary?

  Photo Sharing and Video Hosting at Photobucket

2 posted on 11/08/2007 7:11:39 PM PST by Redcloak (The 2nd Amendment isn't about sporting goods.)
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To: blam

My poor dog is developing cataracks and not seeing less and less.


3 posted on 11/08/2007 7:13:34 PM PST by Spunky ("Everyone has a freedom of choice, but not of consequences.")
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To: Redcloak

She’s a b..ch???


4 posted on 11/08/2007 7:14:16 PM PST by BamaBlue
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To: Spunky

Oops! seeing less and less.


5 posted on 11/08/2007 7:14:58 PM PST by Spunky ("Everyone has a freedom of choice, but not of consequences.")
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To: Spunky
"My poor dog is developing cataracks and seeing less and less."

My oldest one is doing the same.

6 posted on 11/08/2007 7:16:12 PM PST by blam (Secure the border and enforce the law)
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To: blam

I know this doesn’t belong here but all you 50 and 60 boomers you are in for a treat.

It’s Ray Charles, Jerry Lee Lewis and Fats Domino playing the piano together.

http://www.dailymotion.com/video/xe5w0_ray-charles-jerry-lee-lewis


7 posted on 11/08/2007 7:16:33 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: Redcloak

Goa’uld


8 posted on 11/08/2007 7:18:14 PM PST by magslinger (cranky right-winger)
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To: blam
The tapetum also causes dog eyes to glow at night.

Thank God. It's the only way I can find my chocolate lab in a dark yard at night using a flashlight.

9 posted on 11/08/2007 7:20:16 PM PST by tsmith130
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To: tsmith130

Same with my Yellow Lab. His eyes glow golden yellow!


10 posted on 11/08/2007 7:23:15 PM PST by Redleg Duke ("All gave some, and some gave all!")
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To: blam

On average men see better at night than women. Women are more sensitive to color than men. It’s all in the rods and cones!!


11 posted on 11/08/2007 7:24:51 PM PST by aliquando (A Scout is T, L, H, F, C, K, O, C, T, B, C, and R.)
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To: blam
In addition to the tapetum lucidum, dogs and cats have all rod vision which means only shades of gray and---easy movement detection. Human beings have a fovea centralis wherein the cones are located for fine detail and color vision.

Question: Turtles have all-cone vision---what for?

12 posted on 11/08/2007 7:25:49 PM PST by Rudder
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To: freekitty
"I know this doesn’t belong here but all you 50 and 60 boomers you are in for a treat."

Here's a treat.

13 posted on 11/08/2007 7:27:16 PM PST by blam (Secure the border and enforce the law)
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To: freekitty

It’s Ray Charles, Jerry Lee Lewis and Fats Domino playing the piano together.

All I can Say is WOW!!!!!


14 posted on 11/08/2007 7:27:33 PM PST by acoulterfan
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To: tsmith130
It's the only way I can find my chocolate lab in a dark yard at night using a flashlight.

My black poodle disappears in the shadows also.

PetsMart has a fiber optic-like collar powered by a button battery. Works great.
We have used a lighted arm band available at Lowe's . They have a greenish reflective coating and are battery powered glowing also. Continuous or flashing.
Either are about $10.

15 posted on 11/08/2007 7:29:18 PM PST by Vinnie (You're Nobody 'Til Somebody Jihads You)
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To: blam

My neighbors little dog has green eyes. The dog looks freaky when the light hits her eyes right. I call the dog “My Little Martian”.


16 posted on 11/08/2007 7:30:53 PM PST by Sacajaweau ("The Cracker" will be renamed "The Crapper")
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To: Redcloak

Is it possible to have a thread on any subject without injecting Hillary ..... please?????


17 posted on 11/08/2007 7:31:08 PM PST by JustaDumbBlonde
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To: GregoTX

18 posted on 11/08/2007 7:32:08 PM PST by GregoTX (The only thing necessary for the triumph of evil is for good men to do nothing.)
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To: blam
A lot better than we do

Albert Payson Terhune said the same thing 80 + years ago.

19 posted on 11/08/2007 7:32:30 PM PST by gusopol3
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To: blam

I haven’t heard that in years. Thank you.


20 posted on 11/08/2007 7:33:25 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: acoulterfan

Out of this world.


21 posted on 11/08/2007 7:34:06 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: Rudder

My guess would be species identification. The distinctive marks on turtles are often very subtle but involve color. Just a guess. The do pre-date the dinosaurs and it could be that they pre - date cones.


22 posted on 11/08/2007 7:35:19 PM PST by aliquando (A Scout is T, L, H, F, C, K, O, C, T, B, C, and R.)
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To: freekitty

Thanks! That was fun!


23 posted on 11/08/2007 7:37:17 PM PST by rockrr (Global warming is to science what Islam is to religion)
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To: blam
How well do dogs see at night?

It's hard to tell. He's been crying so much lately his eyes are blurry.

24 posted on 11/08/2007 7:45:47 PM PST by Prokopton
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To: freekitty
Here's Jimmy Page playing Dazed And Confused before there was a Led Zeppelin.

Keith Moon told him it would go over like a lead zeppelin.

About a year after Jeff Beck and Eric Clapton left Jimmy page as lead guitar in the group Yardbirds, they changed their name to Led Zepplein and I saw their first US performance at the Filmore west in San Francisco, April, 1969.

Be nice to us old timers, huh? Also, click on my name to see my dogs.

25 posted on 11/08/2007 7:47:39 PM PST by blam (Secure the border and enforce the law)
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To: freekitty

Jerry Lee Lewis ping


26 posted on 11/08/2007 7:51:34 PM PST by i_dont_chat (Your choice if you take offense.)
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To: blam

“Here’s a treat.”

And what it treat it was...thanks for sharing.


27 posted on 11/08/2007 7:52:52 PM PST by oldteen
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To: freekitty

THAT was GREAT.....and my husband wonders what I do on FR.....LOL!


28 posted on 11/08/2007 7:54:22 PM PST by goodnesswins (Being Challenged Builds Character! Being Coddled Destroys Character!)
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To: goodnesswins

Just a little fun every once in a while. LOL


29 posted on 11/08/2007 7:58:36 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: freekitty

WOW!!!!!!!!!!!!!!!!!!!!

AWESOME!!! Thanks much!


30 posted on 11/08/2007 8:01:27 PM PST by Bradís Gramma (Mother of the Bride here, treat me with respect for once, will ya? ;))
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To: oldteen

You are welcome.


31 posted on 11/08/2007 8:10:18 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: Brad's Gramma

You are welcome.


32 posted on 11/08/2007 8:10:50 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: blam

I remember The Yardbirds. I remember Led Zeppelin too. Saw him in concert.

Yes, be nice to us oldtimers. We could atleast sing to our songs. LOL


33 posted on 11/08/2007 8:13:13 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: blam

I love your dogs. They are great.


34 posted on 11/08/2007 8:14:45 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: Sacajaweau
My dog's eyes glow blue, My neck is red, and my niece is black...Diversity at its finest ;-)


35 posted on 11/08/2007 8:19:17 PM PST by Joe 6-pack (Que me amat, amet et canem meum)
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To: Joe 6-pack

That a rough-coat German Shepard?


36 posted on 11/08/2007 8:21:56 PM PST by lesser_satan (READ MY LIPS: NO NEW RINOS | FRED THOMPSON/ DUNCAN HUNTER '08)
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To: Vom Willemstad K-9

ping


37 posted on 11/08/2007 8:23:04 PM PST by Cacique (quos Deus vult perdere, prius dementat ( Islamia Delenda Est ))
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To: lesser_satan

He was a Hurricane Katrina abandonee that I rescued, so I really don’t know what all courses through his veins. From his behavior and physical characteristics, I personally suspect he’s a GSD/Border Collie mix with a dash of cartoon thrown in for good measure.


38 posted on 11/08/2007 8:24:57 PM PST by Joe 6-pack (Que me amat, amet et canem meum)
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To: aliquando
On average men see better at night than women. Women are more sensitive to color than men. It’s all in the rods and cones!!

I’ve also heard that women have better depth perception then men, making them naturally better at shooting guns (sharp shooting/target practice) than men. Women are also naturally better at multi-tasking.

So since women are generally more “sensitive” than men; lesson to be learned by men; Never pi$$ off or cheat on a “Second Amendment Sister” – she’s got all the attitude and perception and the fire power to back it up even if you think she’s distracted by her domestic chores.
39 posted on 11/08/2007 8:26:35 PM PST by Caramelgal (Rely on the spirit and meaning of the teachings, not on the words or superficial interpretations)
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To: Joe 6-pack

Love it.

40 posted on 11/08/2007 8:28:19 PM PST by blam (Secure the border and enforce the law)
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To: Joe 6-pack

Your family is beautiful. Thanks for sharing.


41 posted on 11/08/2007 8:53:16 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: freekitty

Thanks, that was some extra fine music...


42 posted on 11/08/2007 8:57:40 PM PST by Mjaye (Some folks close their mouth only long enough to change feet.)
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To: freekitty
"Your family is beautiful..."

I came from a highly dysfunctional family, but they all got better after I left home ;-)

43 posted on 11/08/2007 9:04:40 PM PST by Joe 6-pack (Que me amat, amet et canem meum)
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To: Joe 6-pack

Me too. LOL


44 posted on 11/08/2007 9:07:09 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: Mjaye

You are welcome.


45 posted on 11/08/2007 9:07:37 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: blam
This guy likes Elvis. LOL Photo Sharing and Video Hosting at Photobucket
46 posted on 11/08/2007 9:10:45 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: freekitty
You Ain't Nothing But A Hound Dog
47 posted on 11/08/2007 9:18:16 PM PST by blam (Secure the border and enforce the law)
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To: blam

I love it.

Does everyone know that Jerry Lee Lewis cousins are Jimmy Swaggart and Mickey Gilley?


48 posted on 11/08/2007 9:24:20 PM PST by freekitty ((May the eagles long fly our beautiful and free American sky.))
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To: blam; Salamander

I think it’s time for someone to post “Master of the Obvious.”


49 posted on 11/08/2007 9:28:26 PM PST by shibumi (".....panta en pasin....." - Origen)
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To: blam

LOL!!!

That looks AND ACTS like some dawg I know & love.....

:)


50 posted on 11/08/2007 9:39:33 PM PST by Bradís Gramma (Mother of the Bride here, treat me with respect for once, will ya? ;))
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