Dogs' Eyes Have Changed Since Humans Befriended Them (2019)
theatlantic.com
theatlantic.com
Abstract:
> Domestication shaped wolves into dogs and transformed both their behavior and their anatomy. Here we show that, in only 33,000 y, domestication transformed the facial muscle anatomy of dogs specifically for facial communication with humans. Based on dissections of dog and wolf heads, we show that the levator anguli oculi medialis, a muscle responsible for raising the inner eyebrow intensely, is uniformly present in dogs but not in wolves. Behavioral data, collected from dogs and wolves, show that dogs produce the eyebrow movement significantly more often and with higher intensity than wolves do, with highest-intensity movements produced exclusively by dogs. Interestingly, this movement increases paedomorphism and resembles an expression that humans produce when sad, so its production in dogs may trigger a nurturing response in humans. We hypothesize that dogs with expressive eyebrows had a selection advantage and that “puppy dog eyes” are the result of selection based on humans’ preferences.
I can't really back this up, but it's something I've noticed.
What I like about your surmise is that, AFAIK, canis familiaris is the only animal other than the great apes that understand gestural ostention (if you point at something a cat will look at your finger while a dog will look at the thing you Re pointing at). As a pack-hunting animal this silent communication is pretty important for dogs and you can see how it could have adapted to humans.
I just did a quick search and there is a recent paper alleging that house cats have some ability to recognize gaze but not gesture, which also suggests this mechanism might be at work.
For example, if a dog goes into a room with a stranger and the stranger then points to one of several buckets, the dog will generally go over to that bucket. This is without any prior training or experience to pointing on the dog's part.
This apparently doesn't work with children so the theory was that over time, the dogs that responded best to human body language were more likely to survive due to getting more treats etc.
Smart dog.
My dog only needs to be given a treat once by a shop owner and every walk afterwards he’ll go up to the door of that shop.
I took him with me to pick up a framed picture once and the shop owner had a few treats for him. We don’t often go by this shop and this was awhile ago. And now when do walk past he pulls a bit to suggest we go inside.
Or if they find some food under a bush or something - they’ll check quite a few times later to see if it magically restocked.
They also try things out to see if it works in getting them food. Which is why it’s important to not fall for their tricks. Easier said than done as they know how to use their facial expressions to get what they want.
When it comes down to it, dogs simply have a lot of time on their hands. They get good at figuring out which sounds and actions mean what at certain times. And they figure out how to manipulate that. Almost like inmates that have nothing to do all day but think up schemes.
They’ll get away with whatever they can.
But it wouldn’t be a good life for a human or even a wild animal. My dog has no freedom or agency and is 100% reliant on me for food, exercise, entertainment, etc.
He can do what he wants within the limits of what I’ve trained him as acceptable (can go in the bed, but not the couch for example) but he isn’t free to leave. He is 100% subject to what I feel is best for him.
Now of course this relationship is mutually beneficial (I assume he’s happy - he gets healthy food, lots of exercise, and treats and toys as well as affection when he asks for it) but even if we had a true post scarcity world I would not want to live his life within the context that I’m a human.
Also they have a mental map of every single squirrel they've seen in town.
Dogs vision is about 20/200 in general, and they can only use their lens to focus 1-2 diopters (compared to about 6 for people).
Dogs can track movement and see in low light better than we can. The way that he did an eye test was simply to drop a cotton ball, the difference before surgery and 2 days after surgery was stark. He would ignore it before, and afterwards his head followed it.
This goes against my experience. When I was dog sitting my mother's dog a few years ago and we were going for the final walk of the night, she'd regularly get surprised by people passing us from the opposite direction. She'd notice them 1-2 meters away and would jump back and bark, while I was easily able to see them 5-10m away. I've had similar experiences with another dog.
Would they notice them better if they were moving side to side instead of slowly becoming bigger while walking towards us?
Also, maybe the dogs just assumed that /you/ would be looking out for any "enemies", and were then just surprised because you didn't warn them about the impeding "attack" while they had other things in mind ;-)
Soon tho, her nose will pick me and I can then see her eyes 'click' on me eventually. I use that trick to keep her "worried" she'll lose me, so she keeps checking on me at shorter intervals and control her urge to follow a yummy smell.
The interesting thing is that on the other hand, she has no problem tracking a moving object in flight at 100m, like a pigeon. Once I was shooting clay pigeons, and missed one overhead, and a few minutes later she came back all happy with my unbroken clay target, she had tracked it, marked it, and retreived it!
I'd be careful with this one. I thought the same when I got a puppy, I'd heard similar repeated (often 20/75 is mentioned as well), and especially that they're not supposed to see well in the dark. After his adolescence my Texas Heeler seems to have excellent vision. He regularly spots small birds, piglets, humans, etc at a distance of 1/4 mile through our window (that's as far as the view goes, but many of the objects he sees rival in size what a human can see at a similar distance). Nighttime does not seem to effect this much. I'm sure his vision is at least 20/40, probably even better than 20/30.
He also seems to have more aggressive pattern recognition through partially obscured sightlines. e.g. seeing a deer or human from just a tiny visual sample viewable through dense trees/brush. However, while this seems to have higher sensitivity than humans (sees the deer when humans dont) it also seems to have somewhat lower specificity (occasionally he thinks something is there when it really isn't).
While this could be due to some Dingo genetics not found in other dogs (unique to Australian Cattle Dogs), it's worth noting that Icelandic Sheepdogs were bred partly to defend unusually small icelandic sheep/goats from unusually large birds of prey that eat them (the white-tailed eagle). Therefore they bark at everything that flies, and some owners have noted that they sometimes bark at birds or airplanes that are quite difficult for humans to see.
My personal hypothesis is that there is wider individual variation in canine sight acuity than is acknowledged by the typical rules of thumb.
https://en.wikipedia.org/wiki/Neoteny#In_domestic_animals
We breed animals for bigger eyes and other features to make them cuter--to make them look more like babies.
https://www.scientificamerican.com/article/tame-theory-did-b...
https://www.scientificamerican.com/article/is-the-gaze-from-...
Dogs are probably the most heavily bred animal in the last 300-400 years. Many (most?) breeds of dogs only exist because humans specifically bred for certain traits.
When breeding for behavioral traits, a dog with expressive eyes who can make humans feel a connection has gotta be a winner over ol wolf eyes over there.
https://en.wikipedia.org/wiki/Domesticated_red_fox
https://en.wikipedia.org/wiki/Dmitry_Belyayev_(zoologist)#Be...
Horse, cow, pig, sheep, dog, and rabbit.
What other at all reasonable way could it work?
See https://en.wikipedia.org/wiki/Domesticated_red_fox#Experimen...
> Out of the 60 western lowland gorillas they considered, only 30% had completely dark scleras. The remaining 70% had some degree of white in their eyes. Of these, a small sample of 7% had all white, human-like sclera.
http://www.bbc.com/earth/story/20150808-gorillas-with-human-...