When I walk my dog after dark, can he see the little lights up in the sky too? Or is his vision too poor?
A dog’s visual acuity is quite low as compared to a human. Some good information here, and some comparisons of human/canine vision here.
Based on that information, I’m guessing no.
We don’t necessarily care about acuity in the sense of resolution. We can’t resolve stars either (except for the sun). Whether dogs sense bright spots depends more on how much light a spot has to emit to appear bright to them. I’m going to guess they can see at least a few of the very brightest stars.
Sirius, for example.
According to the link above, a dog’s visual acuity is about five times worse than a human’s. Since the visibility of stars is usually limited by background light, the lowered visual acuity should require about 25 times as much light for a star to be seen. In dark skies, all of the stars in the big dipper should be visible to a dog. Venus, Jupiter, and bright stars like Sirius should be visible even with some light pollution.
Dogs are partially colorblind (they only have 2 sets of cones instead of 3 like we have) and don’t see details in daylight as well as we do. They also see motion better than we do, though. Basically, they have a higher concentration of rods and a lower concentration of cones than we do, IIRC, and the proportions of where those types of cells are concentrated in their eyes differs from ours.
However, dogs also have a structure in their eyes called the tapetum lucidum which is right behind the retina and reflects light back onto the rods and cones for a second chance to pick up low light levels. Humans don’t have this. This structure gives dogs better night vision than what we have. (ETA - cats have this structure too, as do many nocturnal hunters)
I honestly don’t know how it works out, but I suspect that the tapetum lucidum more than makes up for he smaller concentration of cones, allowing dogs to see stars better than we can. That’s just a guess on my part though. This isn’t my field of expertise. Maybe one of our resident animal/biology experts can comment on this.
They can’t see them very well, but they can smell them.
Cones aren’t much use for seeing stars, anyway. Rods are much more efficient than cones for detecting faint light.
Everybody knows dogs can’t look up.
I saw what you did there.
I’d guess the lowered visual acuity might not be an issue here for seeing at least some of the stars. A dog’s vision is generally given as about 20/75. My uncorrected vision is worse than that, and I can see stars without my glasses. They’re just a bit fuzzy compared to the more distinct pinpoints I see with my glasses on, and I can’t see the fainter ones.
Incidently, it’s the tapetum which is partially responsible for the dog’s lowered visual acuity. It helps gather more light, but at the penalty of blurring the retinal image.
Of course, as dogs aren’t nearly as visually oriented as we are, they probably don’t care about them.
Boo-hoo 
That question makes me think of Laika.
They especially like to smell Uranus…
cue the Urectum joke
Quote:
Originally Posted by Ulfreida View Post
***They can’t see them very well, but they can smell them.
They especially like to smell Uranus…
Very funny.
That depends on the breed.
And hear them.
That’s what Big Al says.
Is there a reason that dogs would need to SEE stars? After all humans can see them and with a few exceptions (such as Polaris) that particular skill is of limited use. Would there be an evolutionary advantage for dogs to be able to see them?
After all, their dispersal across five of the seven continents (Australia and Antarctica don’t count as we introduced them there) states their current evolutionary track seems to be working out pretty well for them without the ability…
I’m thinking they can probably see them. They just never notice them.
Birds can recognize star patterns and use them in migration. While I’m not sure if this capacity has been demonstrated in dogs, it’s possible that in some circumstances recognizing the positions of certain stars and star patterns could assist with orientation at night.
Is there some line of reasoning waiting in the wings here, such as “humans have no evolutionary need to see stars, and we can see them, and dogs have no evolutionary need to see stars, so they probably can”?
There is no need for humans or dogs to see stars, but there is a need for both of us to be able to see stars. The same eyes that see stars also see a lot of other more immediately-relevant things, and any eye that’s good enough to see those other things will also be able to see stars.