
Dogs’ Eyes Have Changed Since Humans Befriended Them - gilad
https://www.theatlantic.com/article/591868/
======
Joakal
This is a good opportunity to educate the general [HN] community about dogs:

1\. They can only see blue/yellow. Not like humans' RGB.

2\. They are short sighted. For far away objects, their sight is like a T-Rex,
they can see moving objects, not stationary objects. Remain still, and they
can't see you. Then again, they can smell you, especially if it's downwind.

3\. Their flicker fusion threshold is higher than humans. If you show them a
cute mobile picture of a baby, they'll see a lot of flickering. As well, did
you know lights have a flicker? If you think it's bad, it's even worse for
dogs which can lead to stress.

More:

[https://dog-vision.com/](https://dog-vision.com/)

[https://www.dogwalkersmelbourne.com.au/articles-dog-
walking-...](https://www.dogwalkersmelbourne.com.au/articles-dog-walking-pet-
sitting/66-dog-canine-vision-seeing-compare-human.html)

~~~
miahi
3\. The flicker fusion issue mostly applies to cathode ray displays and moving
pictures. Many LCDs use flickering light (PWM) for backlight, but usually at
more than 200Hz. Better LCDs use linear current sources for backlight, so
there's no flicker at all. An LCD should be fine even for dogs when static
images are displayed.

~~~
Frondo
Cheap LED bulbs actually flicker significantly, which I realized when I filmed
using my camera's "slow motion" capture at 240 frames per second.

In our bedroom, I put in some LEDs, not realizing there could possibly be a
difference between cheap and expensive ones. One night I filmed my cat doing
something dumb in slow motion, and when I looked at the playback the whole
room was strobing.

It was pretty wild. I might even still have the video, and could see about
posting it somewhere.

~~~
Moru
You don't need slow motion camera, it's enough with most normal catch the
worst offenders in the store if they have those led display sets where you can
see the lightbulb lit. Just shove the camera real close to the lightbulb and
watch the stripes. If no stripes, put it even closer (almost touching) and if
it's still ok, buy it :-)

------
mattlondon
The article (and others at e.g. the BBC) seem to say dogs "evolved" this
capability in "a remarkably short time".

Is it not fairer to suggest that this is not evolution/natural selection at
work here, but rather just selective breeding? I can't think of another
species of animal that has been so widely twisted and manipulated in
appearance by human's selective breeding than dogs.

Seems odd to suggest that _this_ part of a dogs' body was due to evolution,
but that rest of the crazy variety in dogs' body is not? A trait like this
that humans like seems like is an obvious thing to get selected surely?

Or is there some strong evidence to suggest that this was really was nothing
to do with selective breeding?

~~~
NeedMoreTea
I'm mostly comfortable with thinking it's evolution as crazy variety and
selective breeding came very late to the party. Most in the last few hundred
years - lots of the breeds we know are from the 17th, 18th and 19th centuries.

I would guess that for most of our co-existence breeding was up to the dog to
figure out, which might explain the oldest breeds being of a particular
region. Task breeds came very much later.

Edit: Also, how do you selectively breed for muscles that didn't previously
exist?

~~~
silvestrov
> selective breeding came very late to the party

I think that breeding before 17th century was focused on the dogs job such as
hunting wolves (Wolfhounds), sheep herding (Border Collies), watch dogs.

When you don't breed for apperance and only have a low number of different
kinds of jobs for dogs, then you only need very few breeds.

The Irish Wolfhounds were out of jobs in 1786 (no more wolves in Ireland) and
the breed practically died out.

------
sunstone
I wouldn't be surprised if humans haven't changed too since dogs befriended
them. I imagine it's really a symbiotic relationship in the wild.

Both are social animals. Dogs have the speed and the teeth. Humans have the
brain power, stone throwing and cooking. Dogs can mind the human young to a
large extent and humans can feed the baby dogs cooked food. It's win win and a
fearsome combination.

~~~
Causality1
It would be interesting to look for genetic differences between human
populations with a history of intensive domestication like the Maasai and
populations that have no or only recent domestication like aboriginal
Australians.

~~~
rags2riches
Adults that can digest lactose is one trait obviously related to animal
husbandry.

------
hermitdev
In my experience, the dogs ive been around dont generally look sad. The
totality of their facial expressions show their emotion.

Ive a one year old pup, border collie/labrador mix. I can take a quick glance
at his face and know exactly how he's feeling. Probably 80% of the time, its
pure joy. Happy to run around, chew on toys, jump on the furniture and try and
play (unrequitedly) with our cats. About another 10%, he's scared of other
animals he can see out of the Windows of our townhouse and barks incessantly.
The other 10%, I have no idea.

Eyes on a dog don't tell the whole story. Need to look at eyes, ears, back
position, tail and legs to tell.

As I write this, my dog is laying against me, calm amd near sleep. Depending
on perspective, I could see his face as seeming sad, but I know he's just
sleepy. He's only awake because I am and I've not put him to bed yet. But his
face says to me he's calm and content. His breathing is also slowing. His
favorite chew toy is inches from his mouth and against my arm and he's content
to let it stay there; that's how I know he's tired. If you were to just look
at a photo of my dogs face right now, he might appear sad, but I know hes just
calm and sleepy.

~~~
NetOpWibby
Damn, I cannot wait to have a dog.

~~~
jyriand
Getting a dog should not be an emotional decision. I have a dog and sometimes
it's a lot of work. Feeding, pooping, pissing, neverending fur in the house
and on my clothes, vet, constant attention seeking etc. Just to mention a few
things. And if you need to travel you need a babysitter for your dog. It's
easier if you have a backyard where the dog can chill.

~~~
maccard
Can confirm. I am sitting here with a 9 week old puppy that I've had since
Friday. It's relentless at first.

~~~
hermitdev
I feel you. When we got our rescue puppy, we were told he was around 8-9
weeks, but turned out he eas about 6 weeks old when we took him home. He was
transferred to a no kill shelter outside of Chicago from a kill shelter in
Kentucky. We took him home the day he was transferred. We had to bottle feed
for a few weeks with formula before he was able to transition to wet food and
them a few weeks later gradually transitioned him to dry food.

I spent about the first week sleeping on the floor next to him to make sure he
was comfortable and to take him out if he started whining.

We were also told to expect him to top out around 35 lbs. We had him neutered
on Black Friday last year. Figured he was born about May 1st last year. When
he got fixed he was already 45 lean pounds. A year after bringing home, he
seems to have peaked at 60 pounds, nearly twice what we told to expect. He
definitely has tons of energy and is very athletic (he can easily jump
entirely over our couch). He could easily clear the baby gates we have to keep
him in the living room/kitchen in our townhouse. He did it once without
thinking, chasing one our cats upstairs.

First 3 months or so, there were a lot of accidents with urinating and
defecating in the house. And he had worms when we first brought him home. I
had to carry him up and down the stairs for that period, as well. At firat
because he just couldn't get up and down the stairs on his own, and then later
to prevent him having an accident before getting outside (never had an
accident while I was carrying him).

A year in, he's fairly well trained, but we still have some problem areas like
barking and jumping on people. He's crate trained. He sleeps in his crate
overnight and when we're away from home for a bit. My wife works from home and
sleeps in a bit and he's gotten used to me taking him out early in the morning
to do his business and goes right back into his crate on his own after having
a bit of food and water until my wife wakes up an hour or so later.

~~~
maccard
Yeah the stairs was something I wasn't quite prepared for - I live on the 4th
floor and have 60 steps to my garden, I have to carry our pup up and down
every 2 hours at the moment (or less if she's eaten recently). She's never
peed in her crate or on either of us, which is great but she has done so in
the house a few times when we're ever so slightly distracted, but we're
getting slightly better at it.

Glad to hear things are working out for you :)

------
NeedMoreTea
Dogs' eyes _don 't_ generally look sad, especially if they're quizzically
raising _one_ eyebrow. Why change the title from the much more interesting,
and accurate original?

"Dogs’ Eyes Have Changed Since Humans Befriended Them"

I was actually expecting a dire clickbait sort of article, when it actually
turns out to be substantive and interesting.

~~~
gilad
[poster here]: Interesting find - my phone showed the title as 'Why Do Dogs
Look So Sad?', where the actual article's title is different. Looking at the
page's source code under the <title> tag shows these are different. I chose
the shorter version (nevermind dropping the 'so' in 'so sad' cause that's
really click-bait-y). My assumption was that readers would know that the
source (the Atlantic) is a reputable publication and assume the article is of
substance. It's interesting that even the Atlantic needs to resort to changing
the title to get those coveted clicks. In the future, i'll strictly post the
_actual title_ over to HN submission.

~~~
NeedMoreTea
Hm, never knew Atlantic played that game too. I know Ars A/B tests titles, and
that a few of the buzzfeed type publications put a social title (ie clickbait
fest) for the first day or two while a piece does the rounds of Facebook and
Twitter, and replace with a sane "forever" search engine title later.

At the other extreme there's the odd dry-as-dust titled technical article that
really needs some editorialising or at least posting on sub-head to have any
chance of interest.

------
_bxg1
One of my favorite factoids is that the human-dog symbiosis evolved _twice_ ,
in two unrelated corners of the world, at around the same time. It was meant
to be.

~~~
henryackerman
Got a source on that? Seems like an interesting read.

~~~
_bxg1
[https://science.sciencemag.org/content/352/6290/1228](https://science.sciencemag.org/content/352/6290/1228)

------
taneq
They're talking a lot about the LAOM muscle which raises the eyebrow - I
always thought it made dogs look more anxious than sad when they tense it -
but they don't really talk about the RAOL muscle much.

> With dogs, Horowitz points out, we’re so driven to connect that we often
> search for “smiles” in the shapes of dogs’ mouths.

I think a lot of the "smile" facial expression you see on dogs is produced,
not by the mouth, but by the RAOL muscle pulling the corners of the eyes out
slightly to mimic the way humans' eyes squint slightly when we smile.

In any case, it'd be surprising if dogs _didn 't_ have some behavioural /
communicative adaptations, given that their role in our lives has historically
been a collaborative one. Look at all of the dramatic cosmetic changes we've
made in selecting different breeds of dog. Surely selecting for increased
utility as a hunting or farming animal would exert even more pressure?

------
jumpinalake
I wish this article included photos comparing the look of a dog face when
using vs not using the cited muscles.

------
hjk05
As first reading the title I thought: “Really, that’s very interesting” Then I
realized that almost everything about dogs have changed since humans
befriended them. They literally went from wolves to pugs. Taking that into
consideration it’s not at all surprising that the eyes changed too. Of cause
it’s still interesting to dive in exactly how they’ve changed.

------
ralusek
> By evolutionary standards, the time since this split [from wolves] has been
> remarkably short for two new facial muscles to have developed.

2 facial muscles? What about Chihuahuas to Great Danes, is that not a more
impressive evolution than 2 facial muscles?

~~~
Raticide
I think it's because chihuahuas and great danes have all the same bits, just
with different scales/shapes. Where as entirely new muscles take a lot more
work to evolve.

~~~
barry-cotter
I'd be very surprised if Chihuahuas and Great Danes literally have all the
same bits. Canines are the most morphologically diverse animal, surpassing
even humans. If there aren’t dog breeds that all have or lack a particular
muscle, type of hair or bone I’ll be very surprised. Poodles have webbed feet
for one, or just consider how some breeds have floppy and others pointed ears.

It’s reasonably likely the muscles that are universal among dogs existed among
wolves at very low frequency and just exploded in frequency once they started
hanging around humans. These kinds of hard sweeps happen when there’s either a
very useful _de novo_ mutation or a new environment makes a previously
irrelevant or disadvantageous allele or trait beneficial. In humans think
lactase persistence which was pretty much nonexistent 5,000 years ago or the
Tibetan altitude adaptations which derive from the Denisovans who were living
on the Tibetan plateau over a million years ago.

~~~
solidsnack9000
Did a cursory search and it seems to be common wisdom that all dog breeds have
the same number of bones and muscles.

 _While there are many differences between breeds and individual dogs, there
are also common factors that link them together. For example, all breeds have
an excellent sense of smell and hearing and have the same number of bones
which are tied together by the same number of muscles, tendons and ligaments._

[https://breedingbetterdogs.com/article/structure-and-
movemen...](https://breedingbetterdogs.com/article/structure-and-movement-
pt-1)

~~~
Izkata
> same number of bones

This seems wrong. What about breeds with significantly different tail lengths?

~~~
undersuit
Think about this: all mammals have the same number of neck vertebrae, 7, from
giraffes to humans to mice, with the exception of (some)sloths and manatees.

That being said, dogs will have between 6 and 23 bones in their tails
depending on length.

------
bmurphy1976
I always found dog eyes interesting. Some dogs have eyes that very animal
like. I grew up around Miniature Schnauzers and their eyes are eerily human.
The biggest difference is that the iris is a little too big. Were it not for
that, I'd have a hard time distinguishing their eyes from ours.

I find that to be rather astounding actually. Given the wide variety of
expressions Schnauzers at least are capable of emoting, it's pretty amazing
how easy it is for two unrelated species to communicate on such a level. They
speak a lot with their eyes. Look closely, you'll be amazed.

------
ekianjo
> It’s the first biological evidence scientists have found that domesticated
> dogs might have evolved a specialized ability used expressly to communicate
> better with humans.

It could be the other way around: when that kind of ability appeared humans
have very selectively decided to prefer dogs that had that trait. Dogs are
pretty much a human creation (through centuries of selective breeding) so it's
not really evolution rather selection when it comes to this particular
example.

------
skunkworker
I swear this article was timed perfectly with a top reddit /r/aww post earlier
today. Being able to deduce intent and an expression from a dog's glance.

[https://www.reddit.com/r/aww/comments/c1qt1x/doggos_polite_a...](https://www.reddit.com/r/aww/comments/c1qt1x/doggos_polite_and_subtle_implication_that_he_is/)

[https://gfycat.com/healthyfaintbilby](https://gfycat.com/healthyfaintbilby)

------
thebeefytaco
Direct link to the study referenced:
[https://www.pnas.org/content/early/2019/06/11/1820653116](https://www.pnas.org/content/early/2019/06/11/1820653116)

------
brazzy
[https://www.smbc-comics.com/comic/wolves](https://www.smbc-
comics.com/comic/wolves)

------
MarcScott
Isn't this better described as selective breeding, rather than evolution?

Maybe we haven't consciously bred the trait into dogs, but we might have
selected such dogs for breeding, over litter mates that never made eye
contact.

~~~
arnarbi
For the dog, it's just evolution under some environmental factors. One of the
factors just happens to be human behavior.

(But it's typical and common human hubris to not call nature nature when it
includes us.)

------
olalonde
> objectively cuter

For sure.

