13 Very Important Dog Questions, Answered With Science

Prepare to be heartbroken, guys.

Have you ever wondered what's going on inside your dog's head?

We asked our colleagues for their pressing canine questions, and then put them to dog expert and author of In Defence of Dogs (Penguin, 2011) John Bradshaw to get some answers. Here's what he told us.

1. "Do dogs get sad when their owners go to work and they're at home alone?"

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It's bad news for dog owners who have to leave their pup at home during the day.

"They do get sad," says Bradshaw. "Dogs are very attached to humans. It's the way they live alongside us, by watching us and trying to work out all the time what we're thinking and what we're doing. When we're not there, they feel disoriented and anxious."

Different dogs will express this in different ways – Border collies tend to pace around because they're quite active, whereas Labradors are more likely to chew on things. "Each dog has a different way of expressing its distress – some will pace, some will howl, some will bark, some will scratch at the door or dig in the sofa," says Bradshaw.

Even if your dog just curls up and goes to sleep while you're out, seemingly peacefully, that doesn't mean they're not stressed.

In an experiment Bradshaw ran with Channel 4, he filmed dogs that were left at home during the day to see what they did. Dogs that didn't look stressed during the time their owner was out still had high levels of stress hormone in their urine. "It shows that the dog has come to learn there's nothing it can actually do to make the owner come back, but it's anxious and stressed all the time the owner's out," he says.

But all hope is not lost, because there's a training scheme, developed by Bradshaw and available from the RSPCA website, you can use to help your dog feel more at ease when you're not around.

2. "Is there a scientific reason why puppies do that head tilt thing?"

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"It's a natural piece of dog behaviour," says Bradshaw. Sometimes they do it to hear better, but puppies also tilt their head to the side as they approach other puppies to indicate that they're playing.

Bradshaw says that dogs would probably grow out of tilting their head during play, but we could be reinforcing the behaviour by rewarding them for it.

"All dogs will repeat anything that they think will get our attention, particularly if it's the kind of attention they like," he says. "And so puppies learn quite early on that people make a fuss of them after they've done it, and so they'll keep doing it right the way through into adulthood."

3. "Do working dogs like guide dogs get stressed at work?"

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"A lot of the stress in a dog's life comes from being outside of their comfort zone as far as what they're expecting to happen next," says Bradshaw. "That's why puppy-farmed puppies are constantly stressed, because early on they did not learn about the world."

But guide dogs get a lot of training to deal with situations they'll come across while at work. "Teaching a service dog what to do when they encounter something that scares them is part of the training for guide dogs," says Bradshaw.

So, as long as they've had the right training and get plenty of breaks, a service dog is actually much less likely to get stressed than any other dog.

4. "Can dogs really die if they eat too much chocolate?"

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Chocolate contains a chemical similar to caffeine, which dogs and cats are both more sensitive to than us. "The reason that dogs get poisoned and cats don't is that cats don't have a sweet tooth," says Bradshaw.

But dogs don't break down the chemical, theobromine, like we do, so it builds up in their bodies, and can cause irregular heartbeats or fits. "The theobromine will stay in the dog's system for days, so the heart attack could happen three or four days after," says Bradshaw. "Occasionally, small dogs who eat a lot of chocolate are known to die. There are maybe 10 or so in the United States each year."

The key thing for dog owners is to get the dog to throw up, and then take it to the vet, who can give it drugs to reduce the effects.

5. "Can dogs really sense earthquakes?"

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There's no scientific evidence for this, but there are a couple of things that make it not entirely implausible, says Bradshaw.

The first is that dog's paws are very sensitive to vibrations, so they may feel tremors through the ground before we do. "They may feel something funny through their feet," he says. "Whether they can really feel it through the background vibrations of the city I'm not sure."

The second is that foreshocks before a major earthquake are thought to change the smell of earth in subtle ways that we don't pick up on. "That's where the dog's very sensitive nose comes in. There's a possibility they're detecting that the ground smells different."

6. "Why do dogs wag their tail when excited?"

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They're showing other dogs (and humans) that they want to interact, but the reason they wag side to side is so it's visible from the front of their body.

It's doesn't necessarily show that the dog is happy. "We don't know enough about dogs to be sure about what emotional background of it is," says Bradshaw. "But it's certainly excitement, and intention to have some kind of conversation."

7. "Why is my dog's nose always wet?"

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It helps them figure out which direction a smell is coming from. "The upwind side of the nose is colder than the downwind side because of the evaporation," says Bradshaw. "So the wet side, the cold side, will tell them that's the side the wind is coming from."

Your dog doesn't know it's doing this, but they know they have to keep their nose wet. "They lick the nose all the time to keep it wet, and if it's a hot day you'll see your dog doing this all the time, and I think it's just a very instinctive piece of behaviour," says Bradshaw.

8. "Why do dogs circle around loads of times before they decide to sit down?"

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If you see your dog do this, they're doing what their ancestors would have done thousands of years ago to trample vegetation to make themselves a bed.

"Of douse, a dog bed isn't usually surrounded by brambles, but they keep doing it," says Bradshaw. "It's a piece of instinctive behaviour and it doesn't do them any harm, and so they never lose it."

9. "Why do dogs sometimes bury their treats?"

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It's another one of those natural behaviours they've never lost.

"Most carnivores bury some of the food that they get, because their food supply tends to be very erratic," says Bradshaw. When they find food but they're not hungry, they bury it for later.

If you notice your dog doing this a lot, it probably means they don't need as much food as you're giving them. "If your dog is burying all its treats, you probably need to cut back on its main meals," says Bradshaw.

10. "How much information do dogs get by sniffing other dogs’ butts?"

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Bradshaw says one of his students studied how dogs behave when they meet new dogs in a park, and discovered something that won't come as a surprise to dog owners.

"It looked as if the whole goal of most of those encounters was to sniff the other dog's butt, and they quite like to be able to sniff the other dog without being sniffed themselves," he said. "The fact that they're so persistent suggests there must be something important about it. We have to assume they're getting a lot of information from it, but we don't know exactly how much."

Bradshaw says each dog produces a characteristic odour and it's likely that dogs use this smell to recognise each other.

11. "My dog seems to know when my partner is almost home and goes to stand by the door. How? Are dogs psychic?"

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"The senses of dogs are different to ours, and I think we don't emphasise that enough," says Bradshaw. "That they can hear up in the ultrasound, and their sense of hearing is even more sensitive than ours."

So what could be happening is that they can hear a car pulling up outside, or something similar, that we can't hear.

"But I suspect that wishful thinking also plays a strong part," says Bradshaw. "People would like to think that dogs can do it, and so they remember the times that the dog did get it right, and not the times it didn't."

12. "Are dogs ever really sad or happy? Or are we just projecting our own emotions on them?"

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TL;DR: Yes, dogs do have emotional lives and can feel sad and happy, but we sometimes interpret their emotions as more complicated than they actually are.

For example, a lot of people think their dog feels guilt when they've done something bad – but that's unlikely to be the case, says Bradshaw.

"Guilt requires you to compare what you've just done with some kind of mental representation of right and wrong, and there's no indications that dogs can do anything as sophisticated as that," he says. "Dogs do have a 'guilty look', but when it's been studied it turns out to be exactly the same as what the dog would do if its owner was about to punish it. It has components of fear and anxiety."

"When the owner comes home and finds the dog's chewed a shoe or something, the owner's body language changes and the dogs pick up on that and get scared because they think something bad is about to happen, and probably it does," says Bradshaw.

So while dogs have a set of gut feelings – like happiness, fear, anxiety – that all mammals have, it's unlikely they have more complicated emotions, such as guilt. "They really are emotional animals, but it's a set of emotions that's more basic than ours," says Bradshaw.

13. "Can dogs understand human feelings?"

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They don't understand that we have feelings – but they are very good at interpreting our body language.

"They're not just good at it, it becomes a very important part of their lives. They get very attached to us and they are constantly monitoring how that attachment is going," says Bradshaw. "They're very sensitive to our body language, but there's no indication that they understand that we have emotions.

"I don't want to imply that dogs are cold, unfeeling animals, because they're not, they feel a lot, but I don't think they actually understand how we feel. The way we behave affects how they feel to a greater extent, I think, than many people imagine."