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plenty of people think of dogs as their
best friends and the fact that we live
with them so closely means that we get
to know them pretty well but sometimes
our furry friends can act in ways that
are surprising beguiling or downright
mysterious and over the years we here at
scishow have answered a lot of questions
about them like a lot it turns out we
all have a lot of questions about dogs
one of the first ones that springs to
mind is are they really color blind or
is that just a misconception
turns out dogs can see color just not in
the way that we do
here's Michael with more
maybe you've heard that dogs can only
see in black and white it's one of those
fun factoids that people like to toss
around sometimes but this like so many
things we talked about on quick
questions is a misconception and the
misconception stems from the fact that
dogs are from a human perspective
colorblind but that doesn't mean they
can't see color we perceive color
through a series of receptors in the
retinas of our eyes called cones and
humans have three kinds each of which is
activated by a specific wavelength of
light corresponding to a certain set of
colors most humans have cones that can
detect blue green and red wavelengths of
light but dogs kind of like humans who
are colorblind only have two kinds of
cones that work for dogs the two colors
they can register are blue and yellow so
dogs can't see the color red but they
can see and distinguish between various
shades of yellow blue gray and something
that probably comes through as a dirty
greenish Brown so while we see this your
dog sees something more like this it's
not exactly Technicolor but it's a lot
more information than just black and
white and setting the record straight
about dogs partial color vision is
teaching us a lot about how pups
experience the world recent experiments
have found that dogs who are trained to
find dark yellow objects could still
find them even if they were replaced
with very light yellow ones and they
didn't mistake dark blue objects for the
dark yellow ones either suggesting that
dogs can clearly distinguish between
many different shades and colors and
don't just see in greyscale so the next
time you ask your dog to fetch your blue
slippers and he comes back with a pair
of bananas he's not colorblind he's just
messing with you
if your dog is smart enough to pull a
prank like that you might want to
recommend them for doggy Mensa or you
might want to enlist them to test that
old adage that old dogs can't learn new
tricks it's possible we believe that
because older dogs don't learn as
readily as puppies but research shows
that teaching them new tricks could be a
really nice thing to do for your senior
pups here's what the science says
they say that you can't teach an old dog
new tricks but that saying might not be
as trustworthy as you'd think past
puppyhood dogs aren't actually set in
their ways in fact research shows that
not only can old dogs learn new tricks
but teaching them could be a really good
way of improving their quality of life a
few studies have investigated this
specifically for example a group of
European researchers trained two hundred
and sixty-five dogs across multiple
studies as recently as 2017 to push
their noses against a touchscreen it
showed them pictures like flowers cups
and other things and when the canines
picked the right picture they were given
a treat it took the animals a while to
really get the hang of the game but
eventually even the oldest doggie
participants cut on and they could
consistently pick the correct picture to
get a treat while all dogs could learn
to pick the right image the researchers
did notice that dogs over the age of 13
were much slower at learning than the
younger ones and that's because dogs
like humans take longer to learn things
as they get older dogs cognitive
development parallels ours in some ways
just like kids seem to be faster at
picking up new languages than adults
puppies seem to be generally quicker on
the uptake than older dogs a 2014 study
that tested a hundred and forty five
Border Collies on skills like memory and
attention found the dogs faculties start
to decline as they get older maybe in a
similar way that happens in humans they
also found that older dogs were just
generally less interested in new stimuli
while puppies are curious about anything
and everything older dogs tend to lose
interest in things more quickly or tune
them out entirely so in order for older
dogs to learn new things you have to try
a bit harder to capture their attention
but even though it takes them a bit
longer to learn new tricks that doesn't
mean it's any less important the
researchers think that just like older
humans can derive satisfaction from
brain puzzles like crosswords a bit of
mental stimulation might be great for
keeping older dogs healthy and happy a
twelve year old dog might not have as
much energy to play fetch as she did
when she was a puppy but she can still
benefit from playing games and computer
games like the ones used in these
studies require less energy so they
might just fit the bill the researchers
even suggested their experimental setup
could potentially be adapted to let dogs
play computer games at home so not only
can old dogs learn new tricks research
suggests it's a great idea to try and
teach them it may
a little tougher for them but it seems
to be worth the effort
but what if your dog is tuckered out
from a long day of educational computer
games and just wants to chill for a bit
you know kick back and watch some
YouTube you might have noticed your
canine companion reacting to things they
see on a computer or TV screen
suggesting that they can watch TV at
least sort of it turns out they don't
see exactly what we do when they're
looking at a screen because TV screens
are designed for humans but Doc's
actually process visual information a
little differently here's Hank with the
details by the way this clip has some
brief flashing lights so if you're
sensitive to those just skip ahead until
you see me again
does your dog ever seem more excited for
the next season of Game of Thrones than
you are or like weirdly into barking at
nature documentaries if so like a lot of
our patreon supporters you might have
wondered whether your dog is really
watching TV or if you're just reading a
little too much into things well science
is here to tell you that they are
probably watching it but they aren't
seeing exactly the same thing you are
some dogs just seem to love watching TV
watching habits can vary by breed some
like hounds are mostly motivated by
smells so they are less likely to be
interested in the scent free images on a
screen herding dogs on the other hand
tend to get excited when they see
movement so they may be more readily
drawn to video but regardless of breed
what dogs see on the screen is
definitely not what we see dogs visual
systems are much more sensitive to
flickering which helps them perceive
movement more efficiently so if you were
to start flashing a light on and off
slowly and then ramp up the speed you'd
stop being able to distinguish the
flashes when it's flickering faster than
55 times per second
a beagle on the other hand can see
pulses that flash up to around 80 times
a second the image on an old standard TV
screen refreshes about 60 times a second
fast enough that we can't see the
individual pictures but too slow to fool
our furry best friends so - your pup
your favorite show might look less like
a video and more like dancing in a very
fast strobe light or thumbing through a
flipbook and that's not the only part
that might underwhelm them no matter
what type of TV you have what might look
like a vibrant colorful image - you
could be pretty meh for your dog that's
because a typical scene uses a lot of
hues that they can't distinguish instead
of having three different color
receptors in their eyes like us dogs
only have two so they only see worlds
and shades of yellow and blue but if you
really want Fido or spot to be able to
enjoy TV with you science has some tips
there's nothing you can do about the
colors but you can get a new TV if
you've been holding out on a lot of
modern TVs the image on the screen
changes more than 60 times per second
you can also choose shows that your
furry best friends will find more
engaging dogs can be drawn into watching
videos by noises they already find
intriguing like barking or toys
squeaking and unsurprisingly they seem
to like watching other dogs which is why
we're gonna have a new
show hosted only by dogs for dogs just
dogs that's it you'll probably want to
go for live action not cartoons like
lassie not Clifford dogs are intelligent
enough to recognize photos and videos of
dogs and other animals which might be
why they don't respond so well to
animation probably don't look enough
like the real thing but maybe we have
anecdotal reports from inside the studio
that it does work on at least one dog if
you really want to go all out there are
even satellite TV channels with
programming designed for dogs the
brightness colors sounds and camera
angles are specifically chosen to appeal
just to them what but if your dog is not
interested in TV don't sweat its
researchers haven't actually looked to
see how screen time affects dogs so we
don't know if it has any consequences
long-term and you might think your dog
is already enough of a couch potato in
any case they'll probably be just as
happy may be happier if you go on a walk
and that's good for you too
we've all probably heard that if we love
our dogs we shouldn't give them
chocolate even if they see us enjoying
it and seemed to promise that they would
love it too please just a little taste
once again this comes down to a key
difference between humans and dogs this
time in how our digestive systems
process the foods we've adapted to eat
here are the details
if you have a dog you've probably heard
that chocolate will make your pet sick
and that also applies to other pets like
cats rats and mice but that just doesn't
seem fair why do we get to go to town on
a giant bar of dark chocolate but Fido
shouldn't even have one bite it all has
to do with a molecule called theobromine
which is made up of carbon hydrogen
nitrogen and oxygen atoms and along with
its partner caffeine is one of the many
reasons humans have loved chocolate for
thousands of years both molecules are
dangerous for dogs but chocolate
contains a lot more theobromine than it
does caffeine so it's the molecule to
watch out for like caffeine theobromine
is a type of alkaloid which is a huge
class of molecules that generally
contain rings with at least one nitrogen
atom in them and alkaloids often have
physiological effects on humans and
other animals also like caffeine
theobromine makes our hearts pump faster
our blood vessels dilate and some of our
muscles get more energy which sounds
great but too much of it can make our
hearts pump too quickly and our muscles
contract uncontrollably eventually
leading to nausea convulsions heart
attack and even death luckily for our
taste buds
we humans process theobromine pretty
quickly so that's not something you have
to worry about it rarely sticks around
long enough to cause any harm but our
pets aren't so lucky they process
theobromine a lot more slowly so we can
easily build up and cause those
dangerous effects it's hard to know
exactly why we evolved to be better at
digesting theobromine but it might be
because alkaloids mostly come from
plants and our ancestors ate a lot more
plants than early cats or dogs did
whatever the reason the same amount of
theobromine stays in pets bodies much
longer giving it more time to pile up
and cause harm on top of that most pets
are a lot lighter than humans so it
really doesn't take much chocolate to
make them sick cats don't often get
poisoned from chocolate because they
can't taste sweet things so they're
generally not too interested in it but
dogs sure are your average adult human
would need to eat about eight kilograms
of dark chocolate to get a lethal dose
of theobromine but a medium-sized dog
would only need to eat about one
kilogram and a house cat would only need
a
tenth of a kilogram sweeter chocolates
have less the Oboro mean so the lethal
dose is higher about five kilograms of
milk chocolate for dogs and about a
third of a kilogram for cats but they'd
be sick long before eating that much
meanwhile you and I would have to eat
about half of our body weight in milk
chocolate for a lethal dose which might
sound wonderful but I don't want to see
any of you writing challenge accepted in
the comments because you'd be very sick
way before finishing that much chocolate
among other things I'm trying very hard
not to picture what that would do to
your digestive system but the next time
you decide to indulge in a chocolate bar
or three just keep it to yourself no
matter how long your dog gives you those
adorable puppy eyes
but how in tune with our emotions are
they really do they know we're sorry we
can't give them chocolate or what about
the old bit of folk knowledge that dogs
can smell fear there's actually a bit of
research to back that one up it's
possible the dogs really can sense
certain emotional states thanks to the
chemistry of our sweat and their
incredible sense of smell at least maybe
here's Hank to tell us about it
if it hasn't been said to you you've
probably heard it on TV or in a movie
stay calm around strange dogs because
they can smell fear and they might
attack but until recently scientists
hadn't looked to see if that was true
now we know that they can smell fear but
when they do they don't get aggressive
they actually get scared - dogs have
amazing noses their sense of smell is
ten to 100 thousand times better than
ours which is why they can help us
detect traces of chemicals from bombs
drugs and even people buried under the
snow that's thanks to the sheer number
of olfactory receptors they have up to
three hundred million compared to our
measly six million and to the fact that
relative to their size the part of their
brain that analyzes smells is about 40
times the size of ours but even so dogs
don't rely entirely on their sniffers
when they want to communicate with each
other or with us that usually can use
body language and vocalizations as well
when we tell them they're such a good
dog oh they process the tone of our
voice and the words that we're speaking
in different brain areas just like we do
when other humans talk which means they
do understand what we're saying to some
extent and we know that dogs are good at
picking up on physical signals in fact
studies have shown that they can
differentiate between our emotions based
off of our faces and body language so
for a while most scientists and dog
trainers figured that dogs don't need to
sniff out our feelings they can see it
in our posture and hear it in our voice
it wasn't until recently that
researchers looked directly into whether
dogs can smell fear when we're afraid
the sweat we produce contains different
chemicals than when we're happy or sad
because the composition of our blood
changes in response to hormonal signals
so scientists can stick swabs in our
armpits while inducing different
emotions and then to see how dogs react
to those odors and they did this in a
2016 study published in behavioral brain
research and then found that dog's heart
rates increased when they sniff sweat
from people who watch a scary video
suggesting that they can smell fear but
the animals had the same reaction to
sweat from people who worked out so it
wasn't clear if they were just sensing
physical arousal then a study an animal
cognition and 20:17 did a similar
experiment they had
dogs sniff pads with sweat from people
who watch scary or happy videos or
unused pads but this time the
researchers watched the dog's behavior
afterwards and looked at heart rates the
dogs that smelled the happy sweat were
friendlier to strangers their heart
rates were generally higher than the
controls but lower than the dogs that
had sniffed the fearful sweat meanwhile
the dogs that smelled fear seemed
stressed out seeking more reassurance
from their owners and acting more wary
of new people and like the previous
study their heart rates went out so the
researchers concluded that the dogs were
detecting emotions and reacting by
feeling a similar way sniffing joy put
them in a better mood and the smell of
fear it didn't make them more aggressive
it scared them so it seems like dogs can
potentially smell fear and know how
you're feeling but rest assured the
feeling will probably be mutual
but smell isn't the primary way dogs
communicate with us tails wag ears perk
up and if you're lucky you'll get one of
those doggy smiles and we have our own
ways of communicating with them too we
make very specific changes in our voices
when we speak to dogs as you know if
you've ever veered into the who's a good
boy
territory the really interesting thing
is that this isn't just about us putting
on a silly voice when we see a cute
puppy it actually seems to affect how
dogs interact with us
here's Michael to tell us about the
research
it's hard to resist you see an adorable
puppy in the park or outside a cafe and
all of a sudden your voice jumps up
about two octaves and you're talking
total gooey nonsense who's a good boy
but there's actually a good reason for
this puppy talk and it has a lot to do
with the bond between person and pooch
so-called dog directed speech is
actually very similar to the way we
talked to babies which is called infant
directed speech it's higher pitched
slower and kind of sing-songy compared
to our usual conversational tones
because both dogs and infants are
non-verbal researchers believe we
exaggerate other parts of speech like
melody or pitch to keep their attention
and it seems to work at least in younger
dogs in an experiment in 2017 a loud
speaker played pre-recorded puppy talk
for ten dogs and ten puppies the puppies
approached the speaker more quickly and
sat by it for longer when the speaker
played you'd see puppy talk than they
did for regular adult speech but it may
not just be the tone dogs may pay
attention to the content of our speech
as well which sure dogs can't talk but
dog owners know better than to casually
use words like treat or walk unless
you're ready for the consequences in the
form of puppy excitement in a 2018 study
researchers tested dogs responses to our
content versus our tone by creating a
Miss mash of dog directed and human
directed speech when they played typical
doggie talk in a dog directed voice come
on let's go for a walk the dogs
preferred it to typical adult directed
speech experimenters also read human
scripts about boring human stuff like
going to the gym but it was spoken in a
cute doggy voice they also recorded the
opposite cutesy who's a good boy phrases
in a normal adult voice when they played
the recordings to adult dogs the dogs
had no preference for doggy talk when
the cutesy style of speaking was used to
talk about boring non dog topics
apparently the doggy words mattered too
when it came to getting their attention
and dog directed speech might have
another function to improving the bond
between human and animal dogs and wolves
yowl in a high pitch when greeting each
other and when asking for food or care
from their mother and some scientists
hypothesized that we humans might have
unintentionally hijacked this form of
communication during our domestication
of dogs many thousands of years ago we
might have selected for ones who were
more tuned in and reacted positively to
this way of talking by wagging their
tail or yapping back for example
alternatively we might just train our
puppies from birth to respond to our
cute puppy talk you
away in that 2017 study the author
suggested that the adult dogs may
already be bonded to their owners and
not care what the experimenters were
saying and that's why they didn't care
about dog directed speech like puppies
did and the research overall suggests
that we humans don't just talk to our
dogs this way to be all gushy the dogs
actually respond to it and it
strengthens our bond so don't feel weird
about veering into this goofy dog
directed speech every time you see a
Corgi you're just furthering thousands
of years of companionship
thanks for watching this scishow
compilation which was brought to you
with the help of our patrons on patreon
thanks as always for your support and
your great questions if you're
interested in joining our community of
patrons check out patreon.com/scishow
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you
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