Why dogs tilt their heads and 16 more canine facts

The bonds we have with our canine companions are unlike any other friendships or relationships we have. Some of us love our dogs like children, and it's no wonder. There's an unconditional friendship there that makes everything better, and knowing what's going on inside those precious, perfect little heads can only make us understand them better.

Why do dogs always act hungry?

Even if you just fed them five minutes ago, your dog will probably give you those eyes when you're trying to eat your lunch. If their behavior is to be believed, they're one stagger away from collapsing from sheer starvation: "now can I have the rest of that sandwich, you heartless person? Those steaks? There's one for me, right? Don't mind me as I help myself to this pie you've left on the counter, too."

So what's the deal, Pup? It's normal, and it's thought that this behavior is a holdover from when we first started inviting wild dogs to share our campfires and our table scraps. For them, food was a commodity, and you never knew when your next meal was coming. It was better to chow down on food when it was there, and it's likely that the focus on food is biologically hardwired into our dogs today.

For some dogs, there's always the possibility that they've experienced a life where they really were starving, and even after being rescued and re-homed, they're remembering what it was like to have empty bellies. Vets will often differentiate between begging dogs that act hungry, and dogs whose behavior suddenly changes to become more demanding of food, so it's also important to keep an eye on puppy, in case he goes from begging to ravenous.

Why do some dogs eat poop?

Horse poop, sheep poop, unidentified poop … sometimes, their own poop. It's not like you don't feed them, and it can't possibly taste good … can it?

Poop-eating such a common thing that it has a name: coprophagia. There's a whole bunch of reasons a dog might be doing it, and sometimes it's a problem. Other times it's just a disgusting, annoying habit, made even more disgusting by their attempts to lick you afterwards. Most puppies sample some poop at some point, because puppies are dumb and don't know any better yet. (Most, thankfully, grow out of it.) Nursing mothers will often eat the poop of their puppies to clean up after them, and some puppies will see Mom doing it and think it's what they should be doing, too. Puppy see, puppy do.

Some poops (like cat poops) are just interesting snacks, and that's the only reason they might need to raid the litter box — to see what presents their cat friends left behind for them today. In some cases, it might be a sign that there's some sort of behavioral issue brewing. Do they spend too much time alone? Are they doing it just to get your attention? It's entirely possible.

There are some medical causes for the behavior, too, and if your adult dog suddenly starts wolfing down poopsicles, there might be a problem. If they're not getting enough nutrients, they might be trying to supplement their diet. That can happen if they're on food that's not the best quality, or if they're developing some underlying condition like diabetes. Dogs are smart, too, but dogs can also be kinda gross.

How many words do they understand?

The short answer is, "More than you think." The long answer is a bit complicated, because researchers have found that it depends on a lot of things, from training and an individual's intelligence to breed, occupation, and how they're spoken to.

Right now, the record-holder for the most known words is Chaser, a border collie from South Carolina, who knows 1,022 words. Chaser's owner spent a huge amount of time teaching her not only the different names for things, but different actions. Chaser has shown the ability to join verbs and nouns together to perform particular tasks, and she can even use the process of elimination to select toys that she hadn't been taught the name of. She did it by recognizing that "Uncle Fuzzy" was something she didn't know, so it must be connected to the item she didn't know the name of.

Chaser's an extraordinary case, so how about your precious pooch? Most dogs have a vocabulary roughy equalling that of a 2-year-old, with "average" dogs understanding about 165 different words and phrases. The super-bright class understood around 250 different words, and that's mostly working and herding dogs. That's not entirely surprising, given that we count on these dogs to understand what we're telling them to carry out specific jobs. While research shows our herding friends come out on top, dogs like terriers and hounds recognize considerably fewer words. That might have something to do with their original purpose, as while terriers and hounds needed to simply chase, herding dogs needed to be able to follow commands and make snap decisions on their own, which has translated to smarter dogs today.

How efficient are they at learning new things?

An awesome experiment from Yale University's Canine Cognition Center found that most dogs are not only incredibly good at learning new tasks, but they're very good at figuring out how to cut out extra steps and make whatever they're doing more efficient. How good? They're better at it than a human toddler.

Researchers gave human toddlers a puzzle box and showed them how to solve it. The process involved pulling a lever that did absolutely nothing, and the kids couldn't get their heads around how they didn't actually have to pull the lever to open the box and get their treat. Even if a task step is useless, they still do it. It's called overimitation.

Dogs, on the other hand, were able to figure out which steps they could drop and still get to their end goal faster and more efficiently. Even though they went through the useless steps at first, dogs were able to adjust what they had learned on their own. That essentially means that they listened to the advice they were given, then took it upon themselves to filter out the stupid stuff. That ability suggests they're more efficient and better learners than human toddlers, and honestly? We always knew that.

Why do dogs roll in the worst-smelling stuff on the planet?

Any dog owner will recognize the shoulder lean, the butt in the air … and you know that, no matter what you say, Pupper's just found something fun to roll in. It's making your eyes water already, so how can dogs, with their clearly superior sense of smell, even stand it?

Dog behaviorist Stanley Coren, PhD, took a crack at figuring out just they they can't seem to stop themselves. He noted that the things dogs choose to roll in are usually organic things, whether it's the remains of a dead animal or poop. After going through a bunch of theories that made no real sense, he came to a couple of different conclusions. One is the idea that it's an evolutionary throwback to the days they were living in packs and hunting. Rolling in something stinky likely served to mask their own scent, and might allow hunting packs of dogs to get closer to their prey before they're detected.

He came up with something else, too, and you can think of it in human terms. For us, sight is our primary way of receiving sensory input and information. When we see something particularly powerful, we're moved by it. It's the same thing for dogs, only their sense of smell is their most powerful input. The stronger the smell, the happier they are. So basically, your worst fears are true: Pupper really might be rolling in dead things just because he likes being stinky.

What's with the butt-sniffing?

As a mere human, you're probably baffled by what could possibly be so interesting about the smell of dog butt that other dogs just must smell it. And not just smell — they need to get a good long whiff that's bordering on obsessive-compulsive. Factor in the idea that some dogs have a sense of smell that's up to a hundred thousand times stronger than ours, and seriously, what's with the butt-sniffing?

Dogs aren't exactly smelling other butts … at least, not in the way you think they might be. They're actually getting a whiff of what's coming from something disgustingly called the "anal sac." This is the source of some chemical secretions that contain a huge amount of information about the dog, as poorly designed as the whole thing might seem. One dog can tell a ton from what's coming out of these glands, right down to their new friend's diet and current emotional state.

Right, so what about the elephant-fartsies in the room? Wouldn't other backside smells override any sort of chemical a dog's giving off? Researchers have found that the chemical compounds are only half of the communication network, and that dogs have a super-sensitive receptor in their noses called the Jacobson's organ. This particular receptor doesn't sense any kind of poop smell or fartsies, but it's tuned to the particular acids secreted by the anal glands. It allows them to completely filter out any other scents that might get in the way of receiving this chemical communication, and it's also the same organ they use when they're sniffing around the popular pee tree at the dog park.

So, hopefully that makes you feel a little better. You dog doesn't have a weird fetish after all, just a weird way of shaking hands with their own species and a mildly unfortunate design flaw. Oh and, before you get all judgmental about Pupper's funk, don't forget that humans have the same sort of glands that dogs do. Ours just happen to be located in slightly different places, and that's why some dogs are dedicated crotch-sniffers. They're getting all kinds of information about us there, but really? We'd prefer it if they'd just ask.

What's with the circling?

Stanley Coren is a psychologist who's an expert in dog behavior, and he decided to get to the bottom of this one. He tested 62 dogs on various surfaces to see what kind of behavior they demonstrated before lying down. He found that dogs who were put into an area with an uneven surface (shag carpeting) were three times as likely to spin in at least one circle before they settled down.

Coren believes that confirms at least part of one theory: they're simply trying to get comfortable. Other parts of the theory suggest that this behavior is also hardwired into them from their wild days, and that the circling is partially scaring away any bugs that might bite, kicking away any sharp rocks or sticks, and simply just making the ground more suitable for snoozing.

Do dogs get jealous?

Ever come home from visiting a friend and their dog, and get the feeling that you're being eyeballed for the traitor you are? You absolutely are, and if you think your dog has an issue with the other dog he's smelling on your clothes, he totally does.

Stanley Coren took a look at this one too, and he found some of his first proof in the relationship between a mother dog and her puppies. Let's face it — puppies are adorable, and the clueless little poop-machines are the ones getting all the attention. He observed mother dogs shoving their puppies away in an attempt to get human affection and attention, and it seemed as though Mom was getting jealous of all the loves her own pups were getting.

There have been a handful of experiments done to see how dogs react to unfair situations. In one, two dogs are tasked with doing the same thing, but only one was rewarded. Anyone who has dogs can predict how that one went. Another experiment put dogs in a position where their owner's affection was intercepted by a stuffed dog, and again, you can pretty much guess how that played out. Dogs tended not to get bent out of shape when their owners were paying more attention to something like a book, but when it was another pseudo-dog? Oh, hell no.

Weirdly, this is another time that dogs show distinctly childlike behavior, as the results of the dogs' test were similar to the results of experiments done with toddlers who watched their parents play with life-like dolls instead of them. So when we call them fur-babies, we're not too far off.

Do dogs dream?

As much as we want to, we can't get Rover to tell us what's going on when they start running in their sleep, or making those adorable little *boof* sounds. We can make some educated guesses, though, and the science suggests that they're dreaming just like we do. Monitoring the brain activity of sleeping dogs has shown that there's activity going on in there similar to what goes on in our brains when we're sleeping. Like us, they also have a part of the brain called the pons, which keeps us from acting out our dreams (most of the time). It seems to function the same in dogs — puppies and older dogs seem to dream the most, because the pons isn't as active in those dogs as it is in adult dogs.

Dogs enter REM sleep about 20 minutes into their sleep cycle, and even if they're not running in their sleep, you should still be able to see signs that there's something going on in there. From eye twitches to ear twitches and those little *boofs*, they're dreaming. What's more, it's thought that dogs are dreaming about what's most important to them. A dog that spends his day hiking is likely dreaming about wandering through the woods, while one that lounges in the kitchen all day is probably dreaming about dinner. And dogs with close bonds with their owners? One Harvard psychologist suggests that closely bonded dogs are likely dreaming about their favorite person. Seriously, can they be any more perfect?

Right-pawed or left-pawed?

Just like humans, dogs can be either right-handed or left-handed. Unlike humans, there's an equal chance of your dog being either right- or left-paw dominant, or ambidextrous. There are a few different ways you can test to see which your pup is, and that just involves paying attention to which paw is used to do things like give high-fives and steady toys.

Humans have always had a sort of bias against the left-handed — weirdly, researchers have found that the bias might be alive and well in dogs too. They found that left-pawed dogs tend to be more wary, or even aggressive, toward strangers, and even though it's a relatively slight correlation, most guide and service dogs are right-pawed or ambidextrous, as many left-pawed dogs are weeded out because of temperament.

There also seems to be a connection between how dominant your pup's paw preference is, and how brave they are. Pups that are ambidextrous tended to be more anxious, while dogs with a strong preference to a dominant paw were quicker to adjust to new situations and less easily rattled.

What's with the tail?

It's so easy to get sucked into everything else about a dog, you might overlook what's going on with your dog's tail. It wags when they're happy to see us (and, let's face it, isn't that always?), it wags at dinner time, and it's up during playtime, but researchers have found that a left-wag and a right-wag mean entirely different things. When Pupper sees the person that she's closest to, that usually gets a tail wag to the right. That's when the tail is the highest, too, and careful studies (seriously, where can we sign up for these adorable-doggie studies?) show that dogs tend to wag their tails to the right when they see new people, although the tail was generally lower. Even cats got the same right-side wag, but unfamiliar, pushy dogs? *left-wag, left-wag, left-wag*

What's the deal? Right wags mean that it's the left side of the brain that's working hardest, and that's the side that processes positive experiences, happiness, and excitement. When your dog sees you and her tail starts going, it's a physical display of happy. But, when they're nose-to-nose with an unfamiliar dog that might or might not be friendly, the left-side wag is coming from the right side of the brain. That's where things like caution and fear come from, and that's also where dogs process new experiences and objects.

The height of a tail wag also means different things. A relaxed tail is a relaxed dog, while a low tail is a submissive or ashamed cue, and a high tail can be a sign of dominance or excitement. When their hips get involved with a wag, that's a real sign of happy.

What are the rules of dog play-time?

If you've ever spent any time coexisting with two or more dogs, you've probably seen them play together. Things can go sideways in the same way they do with human siblings, and it turns out that there's a lot of myths about what dogs are doing when they play.

You've probably heard the one about the dog that's showing its belly is being the submissive one. Not true, at least not when it's playtime. Studies have found that playtime behaviors are governed by a different set of rules from non-playtime behaviors, and that's one reason why dogs have so many tells that say, "See, I'm just playin'! This is fun, right?!" Rolling over during play was found to most often be a sort of countermeasure, used to avoid being put into a headlock or bite hold by the other dog, and it was never linked with any other kind of submission. It's also a position that allows the roller (and not all dogs in the study did it) to deliver some play-kicks, and it was also found to be a strange sort of opposite to submission.

The study found that in pairs of play-fighting dogs, it was the larger, more dominant dog who would roll on their back. That, experts say, is likely their way of leveling the playing field, to let a smaller or weaker dog get in some licks and bites. It's called self-handicapping, and it's a way for a stronger dog to encourage a smaller one to play.

Why do dogs chase their tails?

We've talked a little bit about how many different things a dog can say with her tail, but there's nothing that amuses humans more than when she starts to chase it. It's a hilarious behavior, and it's even funnier if she manages to catch it. But what's going on here?

There's a few things that might be happening, and all dogs are different. Some dogs might simply be doing it because they're bored at that moment, and it seems like a fun way to fill the time. For some that do it regularly, it might be a sign of a condition called canine CD — OCD for dogs. These dogs might show other kinds of obsessive behaviors, too, from licking to random barking. Here, it might be a problem but, for other dogs, it can be completely harmless. Some breeds are more likely to do it than others, too, making it one of the weirdest breed-specific characteristics we've seen.

Oddly, there might be a physical component to it, too, and dogs that have high cholesterol tend to chase their tails more often. Basically, they have mood changes that go along with their cholesterol levels, and that likely has something to do with the overwhelming urge to catch that durned tail.

They also might be doing it to get your attention. Do you scold them when they do it? Do you laugh at them? Positive or negative, they might be doing it purely for your entertainment. In most cases, it's a harmless enough behavior. If it does become a problem, though, it might require behavior modification — or even drug — therapy to correct, so don't let it become a problem. They'll never live it down at the dog park.

What does the world look like through a dog's eyes?

The idea that dogs can only see the world in black, white, and gray is a long-standing myth. Studies done at the University of California found that dogs can more accurately be described as seeing the world in shades of blues, grays, yellows, and browns. What they can't see is, weirdly, some of the most popular colors for dog toys on the market today. Things like bright orange and bright red? Nope.

So, that leads us to the next part of our look at dog vision. If they can see shades of colors, how do they process that information, and do they make decisions based on it? We're not entirely sure, but the answer seems to be that they can learn to do just that. One study linked different color boxes with different rewards, and they first taught their dog subjects that picking a dark yellow box meant a meaty reward. Then, they switched it up and presented the dogs with a choice between a light yellow box and a dark blue one. Most went for the light yellow, seeming to indicate that they had associated the color with the reward, not the brightness.

There are a few other fascinating facts about canine vision that might change the way you see your dog's world. Compared to us, dogs are also nearsighted. They tend to be around 20/75, which means things are fuzzy in the distance (which might explain your dog's reaction to things down the street). They have a huge advantage over us in the dark, though, as their eyes contain a lens called the tapetum lucidim. It reflects what light is available (and makes their eyes glow in photos), and while they're not as good in the dark as cats, they're much better than we are. They have a much wider field of vision than we do, too. While we can see about 190 degrees around us, doggie can see around 250 degrees.

How do they make us love them?

The bond between a human and their best dog friend is a special one. Put the time and effort into building up a relationship with your dog, and you'll be rewarded exponentially with a friend who's always there for you, who's always ready to listen, and is always ready to do whatever it takes to get a smile. Listen to some people describe their dog and it's clear that they're every bit as close to them as they would be to a human child. As it turns out, that closeness has a biological basis.

Studies done on dogs and their humans have shown that, when dogs look at the human that means the most to them (and that human looks back), it releases a chemical called oxytocin in both parties. That's the stuff that's in the brains of mothers and their biological children that's credited for releasing a feel-good sensation that strengthens emotional bonds. The same thing happens when we build a relationship with our dogs, and it's a weirdly specific, special sort of reaction. Researchers have also tried the same experiments with wolves (even those raised by humans from pup-hood), and didn't get the same chemical connection.

Other studies looked at just what goes on in human brains when owners who are closely bonded with their dogs were shown pictures of just any old dog, and their super-special-best-dog-ever. The images showed similar patterns to what happened when mothers were shown pictures of their children, and they also suggest that dogs know full well what they're doing. Over the last few millennia, once we started keeping dogs as pets and companions, it's thought that they've adopted more and more childlike behaviors, in an attempt to cement their role in a parent-child relationship. And usually? It works.

How close are you and your dog?

Dogs are man's best friend, and there's a good reason for that. They're perfect. They give us unconditional love, and they don't care how bad a day we've had, they just want to make it better. And they do, but you might not even realize just how in-tune to us they are.

Neuroscientists from Atlanta's Emory University looked at just how connected we are to our favorite dogs. (Don't lie, no matter how many you own, you know you have a favorite.) They looked at what a dog valued more: a food reward, or praise from their Special Person. Dogs were trained to associate a pink truck toy with food, and a blue knight toy with praise and loves. After they had the associations down, they started monitoring brain activity to see just how happy they were with praise or food. Out of the 13 dogs in the study, four were happier with love and attention from their people, while nine were equally happy no matter what they got. Only two made food their priority. They also set up a test where dogs could choose to go to their owners or a bowl of food, and found that again, the overwhelming majority chose their owners.

Not sure where your dogs falls? Try yawning in front of him, and see what he does. We might not be sure why we yawn, but we do know that it's contagious. It's catching for dogs, too, and a study from Duke University's Dognition website found that dogs who share an incredibly close bond with their owners tend to share their emotions. That's most obvious with yawning, and if you and your dog share a close emotional bond, you're more likely to catch a yawn from each other.

Dogs who score high in cunning, emotional manipulation, and attention-seeking behaviors are also more likely to yawn, and we'll leave it up to you to know which one your precious pupper is.

Why do dogs tilt their heads?

Besides how it's absolutely adorable (like everything else about dogs), we know little about why dogs tilt their heads, though we can't help but melt a bit when they do it. Though if you ask some people, that's exactly why they do it.

Dogs are man's best friend for a reason, and part of our connection with them comes from their emotional intelligence being off the charts. One suggestion of why they tilt their heads is that they're reading our emotions and looking for the positive response they usually get when they do it. (That's right, your dog is trying to make you smile. Granted, it might be in hopes of getting out of trouble, but kudos for ingenuity.)

There's a couple other theories, too. Depending on the shape of your dog's head, they may be able to improve their ability to pinpoint the location of a noise if they adjust the position of their ears, clearing their line of sight at the same time. Studies have shown that dogs with longer muzzles tend to do this more, so it's likely there's some kind of physical, sensory benefit they're getting from it. Hold your fist in front of your face to mimic a dog's nose, then move your head to see what sort of difference it makes in your line of sight. Go ahead, we'll wait.

Yet another theory suggests that they're just concentrating particularly hard, trying to read what you're communicating to them and seeing what words they recognize. They're looking and listening for social cues to figure how they're going to react, and waiting to see if you're going to say something good (Ride?! Treat?!) or something bad. Experiments on dogs' interpretation of language found that they'd tilt their heads right when they were spoken to with emotionless words, and left when the words were full of emotion, both good and bad. That seemed to suggest it has something to do with the way they process information, and it might mean they have separate processing centers for emotion and words.

They're such good, smart baby-dogs. So good.

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