Dogs going from light to dark, how do they do that?

[GusNSpot]

So I am out with my dog late at night and I throw a spot light on him. His eyes glow and sometimes I hit him with the full beam in the eyes.

He can then turn and race into the darkest brush and apparently see just fine to run without hitting a tree or whatever.

Shine a bright light in my eyes on a dark night, & I am not running off into the darkest brush, my night vision is toast and I would fall off a cliff in the dark.

So how do dog’s eyes do that?

[Alpha_Twit]

At least some of it in just not having the awareness of the risks involved. Their little doggie brains don’t register potential danger they way ours can and they just happily crash on. Mostly it works out.

[Sunny_Daze]

Respectfully, I think there are other factors at play Alpha Twit.

Dogs are adapted to see well in both light and dark conditions, according to Paul Miller, clinical professor of comparative ophthalmology at University of Wisconsin-Madison.

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.

So your dog may not see the detail that you and I see, but they can see in much dimmer conditions.

Remember that your dog is also getting input from hearing (~4x better than humans) and smell (~10,000-100,000x better than humans). It may seem dark and mysterious out there but your dog has a good idea of what going on.

[Alpha_Twit]

@Sunny_Daze

Respectfully, I think there are other factors at play Alpha Twit.

I don’t doubt that for a moment.

[kayaker]

@Sunny_Daze

Remember that your dog is also getting input from hearing (~4x better than humans) and smell (~10,000-100,000x better than humans). It may seem dark and mysterious out there but your dog has a good idea of what going on.

Their sense of smell is amazing. One of our dogs has been through a scent training course. We used the end of a Q-tip with a drop of balsam oil soaked into it as a training aid. Even after using it for months of exercises, at a point where I could detect zero odor, the dog was able to locate the Q-tip in its screened container hidden in random locations.

If you or your dog is interested, consider nose work classes.

[DCnDC]

@kayaker

Their sense of smell is amazing. One of our dogs has been through a scent training course. We used the end of a Q-tip with a drop of balsam oil soaked into it as a training aid. Even after using it for months of exercises, at a point where I could detect zero odor, the dog was able to locate the Q-tip in its screened container hidden in random locations.

I once had a friend who was attempting to ship something stinky of questionable legality, trying to mask the scent by burying it in a can full of coffee. I spent a long time trying to explain to him why that wasn’t going to fool a dog. Trying to hide something smelly from a dog by burying it in a coffee can is like trying to hide your refrigerator by moving it to center of your living room.

[GusNSpot]

Thanks for all the information folks. Learning day for me.

[Jackmannii]

Anyone know offhand how this works for amphibians?

At times I’ve been out in the garden or on the patio at night and seen a photogenic toad I wanted to take a picture of. I’ve been avoiding using flash for fear of damaging a sensitive amphibian retina - is that a realistic possibility?

[road_lobo]

Also, dogs have whiskers, or vibrissae.

[The_wind_of_my_soul]

Since a few people have brought up dogs’ impressive sense of smell, I have a question related to that: How come dogs (or at least, my dog) don’t seem bothered by horrible smells? I would think if the smell of rotten meat (for example) made me gag, and the dog’s sense of smell was 10,000 times better, it would be that much worse for the dog!

[Kimstu]

@The_wind_of_my_soul

Since a few people have brought up dogs’ impressive sense of smell, I have a question related to that: How come dogs (or at least, my dog) don’t seem bothered by horrible smells? I would think if the smell of rotten meat (for example) made me gag, and the dog’s sense of smell was 10,000 times better, it would be that much worse for the dog!

AFAIK nobody really knows why dogs find smells like rotting meat, excrement, etc., so much more attractive than we do, but it probably relates to their greater willingness to eat things that smell like that.

A more apropos question might be: why are humans so unusually squeamish, from a general mammalian point of view, about so-called “horrible-smelling” things like excrement and rotting flesh? Given that fellow primates such as chimpanzees will eat feces, why are we so revolted by them?

[Der_Trihs]

@The_wind_of_my_soul

Since a few people have brought up dogs’ impressive sense of smell, I have a question related to that: How come dogs (or at least, my dog) don’t seem bothered by horrible smells? I would think if the smell of rotten meat (for example) made me gag, and the dog’s sense of smell was 10,000 times better, it would be that much worse for the dog!

I expect that the difference is that because our sense of smell is so bad, there’s no evolutionary advantage in us doing anything other than avoid “bad smells”. Getting up close to anything like that just exposes us to a danger of infection or poisoning while gaining us no useful information.

Dogs on the other hand get far more information from scent than we do. A dog doesn’t just have more a sensitive nose, they can derive much more complex information about what they are smelling.

A dog that sniffs something like that will get vastly more than just “this stinks” from doing so; so they have a much more nuanced response than just “this smells bad, avoid”. To use a visual analogy we are like some creature with simple eyes that can only see blobs of light and dark, with a reflex to avoid darkness as “bad”; meanwhile they are like a creature with full high-quality color vision that sees enormous differences in what we just see as identical “bad” dark blobs.

[Dung_Beetle]

So you say I’m wasting my time farting at the dog, because he just thinks “Fajitas”.

[markn_1]

It’s rare to see a post where you can substitute “chameleons” for “dogs” in the title, and it would still be an interesting, but totally different, question.

[Sunny_Daze]

@Dung_Beetle

So you say I’m wasting my time farting at the dog, because he just thinks “Fajitas”.

From the restaurant downtown, chicken but not steak

(No idea, actually. My dog sure stinks up the place though.)

[GottaBeMeh]

While it wouldn’t surprise me to learn that dogs eyes can react more quickly to changing lighting conditions than ours, anyone that has ever hunted with a dog knows that a lot of their “seeing” is done through their nose. I’ve many times watched dogs chase squirrels through the woods. But instead of taking a direct path to the squirrel that they see, they invariably keep their nose to the ground and retrace the exact same path the squirrel (or w/e prey) took. And keep in mind, they’re typically doing this at running speed with eyes pointed straight down at the ground. They might as well be blindfolded. So extrapolate that and consider that everything and everyone emits a smell be it a tree, shrub, rock, water, etc.