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.
I am glad you said that. They came up with the name because of a police officer who raise shilohs. Too funny
The English field trials are completely different from our American ones. Without getting into a preposterous amount of technical detail, the American field trials are all about precision in lining retrieves and perfect handling. The British trials, on the other hand, focus more on negotiating heavy cover and hunting for a downed bird with scent as well as sight. The British competition is organized in a very different way, with a group of dogs going forward together and taking turns trying to retrieve a group of downed birds. The highest accolade is for a dog to "wipe the eye" of another dog in his group -- i.e. retrieve a bird that the previous dog was unable to find.
I know a couple of trainers here that train their field dogs in the British style. It's quite a different game.
I think I mentioned before that my daughter wants a White Shepherd simply so she can name it "Silas" . . . (she's just kidding of course, she does want a dog, but only when she has settled down in a house so that said dog has room to exercise and she has time to devote attention to him.)
If I hadn't gotten into Labs I would have had GSDs, but for a first dog and with small children I thought a Lab would be more bombproof. And now of course I think Labs are the best in the world . . . ;-)
Actually those dogs are the mother and father of my girls. Bama is the first pic and Fuji is the second. Then Bama; then Fuji at 4 months old.
I don’t think I have ever seen the American Eskimo; but I have seen a beautiful American Indian dog. You know you can cage them. They just can’t stand it.
I love both the Labs and the GSDs.
That’s what my friend tells me. Everything is different between the English Labs and the American Labs trials.
She considered it a honor to be asked.
Awhile back, our Hunting Retriever Club magazine ran a special feature on 4 or 5 UKC Hunt Test dogs who were invited to Britain to run in a field trial there. These were top UKC dogs and they did very well - although some of the dogs were puzzled at first by the different conditions, they thought it through and noodled it out.
The AKC field trials in the U.S. have gotten so rarified that the UKC started doing "hunt tests" as being more of a realistic test of hunting conditions that a real hunting dog might actually encounter. And the hunt tests got so popular so fast that the AKC had to start offering them too!
I don't do field trials - I'm not good enough - I do hunt tests. My dogs really enjoy it.
This American Eskimo looks exactly like my friend's dog.
They're quite small - usually between around 10 and 15 inches at the shoulder. Beautiful long fluffy double coat. They're not really an Indian dog - they're related to the Spitz and are purely a companion animal, they don't DO anything. But like all the Nordic type dogs they are rather hard headed and problematic to train.
Wow. What a beautiful dog. The spitz, I understand, is a breed used in the foundation of a lot of dogs. Look at the white on that dog.
They actually seem to glow. It’s the whitest white I’ve ever seen on a dog.
They actually seem to glow. It’s the whitest white I’ve ever seen on a dog.
She said they come over here once or twice a year and that’s how they were invited. They didn’t win; but she said it was a great experience.
LOL I don’t show myself because I can’t keep up with the dogs. Keeley is well conformed as is Rosey; however; she doesn’t like the ring. Their ears are a little big, though. Bores her. Rosey on the other hand is a real ham. She is like an angel floating around that ring. I have to stay out of her sight though because she keys off me.
We were in a show training class one time and where was Keeley. Admiring herself in the big wall mirror while everyone else including her sister were already at the other end. LOL Don’t get me wrong; Keeley will win as she has; but she doesn’t relish it. Rosey wins too; but loves it.
Can’t wait to show my boy and see what he does. He is conformationally correct and ears are perfect and a long reach in his gate to die for. Since he has a harum here; he has become big daddy. We will see if he behaves himself; but I have got a wonderful trainer/handler.
Don’t mean to brag; but you know how it is with one’s own dogs be they show dogs or not. I have two others that are not show; but I love them to pieces.
I obviously don't do conformation, with my little dachshund on stilts and my pint size half-and-halfer!
But we do the performance events -- my chocolate has excelled in Agility, she has titles in three associations, including Excellent and Excellent Jumpers in AKC. She also has her first Hunting Retriever title, and we're working on the second level.
(Now don't you apologize for bragging any more!!!)
And this just in . . . this past Monday night, both Ruby and Shelley achieved their Canine Good Citizen titles . . . Ruby by the skin of her teeth (she's still rather an excitable little pup!)
So now they are SHR Sumo's CoDoz Brown Bombshell, AX, AXJ, AD, AJ, CGC, and Candlewood Rock 'n' Roll Ruby, CGC.
I'm glad poor Ruby finally got some letters to put on her name, she might have gotten a complex . . . < g >
Have you thought about doing obedience or agility with your dogs? It’s tons of fun, and you don’t HAVE to run. There’s a lady in our agility club who has terrible back problems and can barely walk about. She has trained her Border Collie to run the agility course by voice and hand signals from a distance, while she just stands near the center of the ring. It’s the most amazing thing!
Oh, those are so pretty. I will have to arrange mine. LOL It’s nice to talk to someone that has an understanding of the dog show world be it agility, show, hunter, flyball.
I thought you had to run the course. I have a cattle dog that woud be perfect and flyball too. She is smart and she is quick. I am still thinking about my pharoah hound. They are sight hounds. The Shilohs are fast; but too big for the course and they get stuck in the tunnels. LOL But they are good hearders which is what group the shilohs are in. They are also not as fast as the border and the aussies. I have a friend that started her shiloh when it was a pup and that had to keep changing in the classes the size of the tunnels because she would get stuck. They grow fast.
A friend of mine did all her conformation ribbons in a shadow box around a professional photo of her Golden. It was REALLY pretty.
You do not have to run the course, only the DOG has to run the course. If it's an AKC course (slow and twisty) it's easy to find a spot where you can stand in the middle and steer your dog. USDAA courses are faster and more wide open, so it's a little more difficult. But USDAA puts a premium on remote handling, because in the Gamblers class you have to handle your dog away to a series of obstacles while standing behind a touch line. (It took Shelley and me awhile to get a pass in Gamblers!)
Boy are things different in competition. Peaches is really fast and can turn on a dime and very responsive to what I tell her. She can be stubborn though. I bet she would something in it.
At least around here, it's very reasonable - $60 for 8 weekly lessons. Entry fees are typically 10-12 bucks per class, with a discount if you enter a large number of classses (in USDAA - AKC there are only two classes - standard and jumpers). Or you can just find an agility trial near you, and go wander around during the day and chat people up and watch the competition.
The woman that runs the show classes also runs a agility and flyball. Right up the street.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.