Sense of Sight

Dogs are far more attuned to movement and contrast as opposed to colour and detail. This is due to the different balance of the types of cells in their eyes - rods and cones. It is the cones that are used for colour perception and in making out fine detail. Humans have around 6 million cone cells, comprising three types, with each type responsible for a different wavelength of light. Humans have trichromatic vision meaning that they can see a full spectrum of colour. It is a myth that dogs can only see in black and white. Dogs have far fewer, 1.2 million cone cells, consisting of only two types which is known as dichromatic vision. So contrary to popular belief dogs can see blue and yellow. So be mindful if you have a red toy on green grass they may find it a bit hard to find it by sight. Both humans and dogs are considered predator species and have eyes placed on the front of their head as opposed to prey species like sheep who have eyes situated on the side of their head. Front set eyes allow binocular vision meaning that they can judge depth and distance accurately. Even with front set eyes dogs have a much greater peripheral vision than humans averaging 60 - 70 degrees greater. Humans can see about 180 degrees around them whereas dogs can see up to 250 degrees, though a dog's peripheral vision is affected by breed type. Flatter faced, short nosed breeds such as pugs and bulldogs don’t have the extent of peripheral vision compared to longer nosed breeds such as labradors or border collies.
Dogs have evolved to see quite well in low light, but have also not lost the ability to see clearly in daylight. The minimum threshold of light needed for vision is significantly lower for a dog than that of a human and they can see up to 4-5X better in low light. In low light so dawn or dusk, you may notice that your dog notices the tiniest rustling movement in a bush even as you struggle to make anything out in the failing light. You’ll also notice that colour is imperceptible in dim light, so superb colour detail vision becomes useless.

Sense of Hearing

We all know that dogs have very good hearing but just how good is it? Noise is calculated in vibrations per second or hertz (Hz). It is estimated that a dog’s hearing falls in a range between 67Hz (the lowest pitch sounds) and 45,000Hz (the highest pitch sounds). If we compare this to human hearing, humans and dogs can similarly hear low pitch sounds with humans measuring slightly lower at 64Hz but as for high pitch sounds dogs have far better hearing with humans only measuring at 23,000Hz. It is estimated that a dog can hear sounds up to 4x further away than humans. The makeup of a dog's ear is not too dissimilar to that of a human. The biggest differing factor is that a dog’s ear is designed to proactively catch sound rather than just receive it - they can move their ears around. It is the mobile outer muscular structure that allows a dog to do this with 18 muscles as opposed to our 6 that manage movement at the base of their ears. Dogs are also able to control each ear separately meaning they have an aural advantage. Even though all dogs have better hearing than humans, certain dogs are more sensitive to sound than others (look at breed specifics who have evolved over time to rely on sound to do their jobs). Dogs that develop noise phobias or sensitivity are usually the ones that can’t filter between active listening (focusing hearing on a specific sound) and passive hearing (when there is noise in the background that you hear but your brain doesn’t actively listen to). It is also linked that noise sensitive dogs are more susceptible to anxious behaviours such as separation anxiety or fearfulness in new situations and took longer to recover from stressful events. Understanding this, it is self explanatory of why it is so important to desensitise and positively associate puppies to scary noises like fireworks, thunderstorms, loud bangs, wind and general everyday life sounds. It is proven that puppies who have been provided sensory education and have been desensitise to noises are less likely to develop noise phobias as adults.

Sense of Touch

It is normal for some dogs to be more sensitive to touch than others. It is important to habitualised a puppy from a young age that human touch is a good thing and that a human hand approaching them (particularly approaching from above the head) is not threatening (they have an automatic defense mechanism that makes them cautious when they see a hand coming towards them). Humans tend to touch their dogs in ways that we touch each other - hug, pat, stroke, touch face and shoulders. Due to a dogs connection with humans they are so keen to interact with us they will put up with being touched in ways they don’t like but it is extremely important to remember that a dog is a dog and not a human which means that they don’t have the same preferences. We must acknowledge and respect this and take the time to think about how we touch our dogs. Touch sensitivity varies from dog to dog but a rule of thumb is you should always be careful when touching a dogs head, muzzle, face, tail, abdomen and paws. Also be mindful when giving a dog a hug as dogs don’t have hugs in their body language repertoire (be mindful when you are putting a human mannerism or behaviour on your dog). A dog has a lot of nerve endings along its spine and towards its tail. In general they also have much thinner skin than humans. Both factors contribute to dogs being more sensitive to touch. Have you noticed whiskers on your dog's face? They are called vibrissae and sit on your dog’s muzzle, eyes and under their chin. They are set into their skin 3x deeper than normal hair. Humans feel the world through their fingers whereas a dog often uses their face. A dog’s whiskers are loaded with nerves that send sensory information to their brain. As they are super sensitive to touch, they detect changes in airflow around the dog’s face giving it an enhanced sense of space around it’s head and if there are nearby objects, helping to compensate for their imperfect vision and is useful to help a dog fit through tight spaces as well as an advance warning system of an approaching hand or object. Even though a dog’s body can be very, very sensitive to touch, with the correct positive exposure a dog can learn to love touch from a human and rely on it. It has been proven that when a human pats a dog it raises their oxytocin hormone (the feel good hormone) and lowers their stress level. When our oxytocin levels increase so does our sense of wellbeing and the world seems a better place. If a dog likes touch, it is mutually beneficial in increasing a dog’s oxytocin level.

Sense of Taste

Dogs have 1700 taste buds compared to humans who have 9000 taste buds. Their taste buds are replaced with new ones about every ten days. Like humans, dogs can pick up on sweet, salty, bitter and sour tastes. They also have receptors that humans don’t have, the first being they have special taste buds that are specifically programmed for meat and within meat they can taste a wider range of flavours than we can. The secondary is that they can taste water. It is thought that this is an evolutionary response to keep dogs hydrated while eating a diet heavy in salty meats as dogs do have salt receptors but they are considerably weak (as a dogs diet is heavy in meat and meat is high in salt it is believed they had less need to develop receptors that could help identify sources of salt) . High salt means more urination which means higher chance of dehydration. The counter is for a dog to drink more. The water taste buds on a dog’s tongue are an important tool in sourcing and detecting safe drinking water. The receptors for each flavour are positioned on different parts of a dog’s tongue - sour and salty to the sides, bitter at the back, sweet at the front. The taste receptors for water are located at the very front.

Sense of Smell

A dog's sense of smell is so much more accomplished than ours. Dog’s see the world through their nose through odour profiles. When they smell they are gathering and processing information about the world around them. It would be like us studying every single brushstroke that makes up the whole artwork with a magnifying glass. It is estimated that humans have 5 millions scent receptors (1 square inch) vs a dog’s 300 million scent receptors (30 square inch surface area) - a whopping 245 million more scent receptors than a human. Your dog can detect smells 100 million times less concentrated than what our noses can detect. The cool, wet mucus found on and inside a dog’s nose catches and traps passing scent molecules, which dissolve in the mucus and aid them with smelling scent. Each nostril can also wiggle independently to gather scents from all directions and smell independently. The equivalent would be if you had two noses on your face working separately. Another notable difference is dogs have slits in the side of their nostrils. When a dog exhales, the air passes through the side slits of the nostrils so that it doesn't contaminate or dilute the scent molecules of the incoming air that the dog is breathing in through the larger central holes. It also helps to create swirls of air which draws in new odour molecules and helps odour build up in concentration over multiple sniffs. Unlike us, dogs have the physical ability to keep the two functions of breathing and smelling separately as they have two passageways inside their nostrils. Around 12% of air breathed in is directed to the olfactory epithelium– a catacomb at the back of the nasal passage, close to the brain used to process smells. The rest of the air is directed to the lungs for the dog to breathe. The Olfactory epithelium is at the back of the nose, close to the brain and is where your dog’s 300 million scent receptors sit. Canine Olfactory Bulbs are 3x larger than those of humans, even though their brains are 10x smaller. It is here where scents are sieved and grouped according to their different chemical compositions. The receptors then send electrical triggers to the dogs brain according to the chemical signals that the scent molecules set off, allowing the dog to analyse what he smells. It is estimated as much as a third of a dog’s brain is dedicated to reading what the nose collects. It is also important to note that dogs have a vomeronasal organ located above the hard palate of the mouth. The information received through this organ goes straight to the limbic system which regulates mood and drives emotion and memory. Because smell and memory are closely linked, meaning different smells can be used to change the way a dog feels as long as the smell is paired with something that the dog likes. Every human has a unique odour or scent signature that only they have. The theory of a dog being able to smell fear is supported by the apocrine sweat glands located in areas such as underarms, genitals, back of the neck and tummy being activated by our emotional state and releasing a highly fatty substance, making it easy for a dog to smell how we are feeling. So if your dog has a habit of going up and sniffing a human’s genital region, especially strangers or someone they have met less often, it is because they are trying to process the abundance of information about the person they are smelling such as emotional state and health. Dogs can smell the chemicals and hormones in different species including humans, and that is why we use them to detect cancer, seizures, covid, etc. And that is why your dog’s behaviour changes based on our emotional state as hormones dictate that. Here are some great ways to visualise and try to comprehend how amazing a dog’s ability to smell is: - If you can smell a spray of perfume in a small room, our dog can smell the same amount in an enclosed stadium and distinguish its ingredients all together at the one time. - Their nose is so powerful that if you were to press your thumb onto glass, a dog can smell your scent for 6 weeks. Where we see and hear something at a single moment, a dog smells an entire story from start to finish. If you watch and see your dog through their nose, you will open your eyes to a whole new world that is happening parallel to ours. You need to allow your dog to be a dog and sniff. Otherwise it would be like me saying to you we are going to go sightseeing but too bad you are blindfolded. It is not fair. It is so important that you allow your dog to engage in “sniffaris”. A sniffari is an outing in which your dog sniffs whatever they like and leads you where they want to go to sniff as long as it is safe. It is a completely different mindset to when you take your dog out for a walk for exercise. The goal with taking your dog on sniffaris is to allow them to explore the world by the way they “see” it - by way of all of its glorious smells. When you are doing a sniffari you should not be worried about the distance to cover as if you allow your dog partake in it correctly, it may take 20 minutes to go 10 metres. I don’t rob you doing things you like to do such as watch Netflix, read a book, enjoy the sunset etc. person specific likes and needs, so don’t rob your dog. If you can’t take your dog for a full sniffari at particular times you can incorporate “ dedicated sniff zones” into your walks. This also helps to teach your puppy that they can sniff when the time is appropriate and that they are not to drag you to every tree or post that contains a smell (which is everyone). A dedicated sniff zone for an example would look like this: From the blue car to the purple letterbox which is 20m apart, that is your dog’s dedicated sniff zone. Prior to the blue car your dog should be focused with you and loose lead walking as they are in that expectation zone. If they try to pull you to a smell you continue to walk and say “let’s go” and reward them for coming with you. You do not allow them to stop to smell. The moment you hit the start of your dedicated sniff zone you can either ask your dog for a sit or pause, get their eye contact and then release them to free sniff by saying “go sniff”. So as long as it is safe, your dog can sniff whatever it wants for however long whileever you work your way through the dedicated sniff zone. When you get to the finish line either ask your dog for another sit or eye contact so you can clearly define to your dog free sniff time is finished and now it is back to loose lead walking and working with you by using a command such as “walking”. Another good point to remember is, if your dog is not coming back to you or is running away, it is not trying to be naughty or defy you. There is a very good chance that your dog is fixated on a smell and can’t comprehend or process other information as their smelling ability takes up a lot of brain power. Think as if they have noise cancelling headphones on. Be smart when you ask something of your dog. Set them up to succeed. If you are not succeeding at asking your dog for a behaviour at a correct time, how can you expect them to do it correctly? Here are awesome videos of a dog’s sense of smell:

A Dog's Senses