Senses in Dogs

Living with a dog is like living with someone from another culture that speaks a different language. Dogs have their own way of communicating that is different from ours and we don’t always understand what they mean or what they need. One way to become more in-tune with our canine companions is to gain a better understanding of how they perceive the world around them. Just as dogs communicate differently than we do, they also perceive the world with their senses differently than we do. Understanding canine senses is one step toward better understanding of our canine companions and why they do the things they do.
The 5 Senses – Let’s explore each of the five senses to get a better idea of how dogs perceive the world around them.

• Smell
• Sight
• Hearing
• Touch
• Taste

Smell
While sight is arguably the dominant sense for humans, smell trumps all other senses in the dog world. Here are a few facts about the dog’s sense of smell:

• Dogs have 20 times the number of smell receptors in their noses than humans

• Dogs can detect smells 100 to one million times less concentrated than humans (for example, some dogs can detect a human scent on a glass slide which was lightly touched and left outside for two weeks)

Dogs’ olfactory lobe—the part of the brain responsible for decoding scent messages—is substantially larger than human olfactory lobe. Furthermore, they have an organ within their nose—called the vomeronasal organ or VNO—that is used for detecting the pheromones, or chemical signals, from other animals and people. Using their uncanny sense of smell, dogs can identify others, determine who or what is and has been in a particular location, and even how those people or animals were feeling at that moment.
What’s more, dogs can pick up smells in bombs and explosives with greater accuracy than human-made chemical detectors, such as mass spectrometers. Other studies has actually shown that trained dogs can detect diabetes, seizure disorders and even certain types of human cancer with 80 to 100% accuracy.
Understanding the canine sense of smell can help us to understand why Fido wants to take 10 minutes sniffing one spot of grass while on a walk and why dogs always insist on the greet-and-sniff with one another. It can also help us to appreciate just how phenomenal the canine sense of smell truly is.

Sight
It used to be thought that dogs see only in black and white. This is not true. Dogs do see colors, but not as many as humans do. Canine color vision is akin to red-green color blindness in humans. This means that dogs can see yellows and blues pretty well, but reds and oranges appear as yellow and green looks white. Thus a dog’s visual world is primarily made of grays, blues and yellows.
Furthermore, dogs are unable to see detail as well as humans can. Conversely, dogs have better night vision than us. The canine eye has more rods than the human eye. These rods are responsible for distinguishing between the many shades of grey twixt black and white, which can help at night when everything appears in these shades. Dogs also have a better ability to detect motion and allow in light under dim conditions than humans. This may help to explain why Rover insists on staring intently out the window after dark, when you can’t seem to see anything of interest out there. It may be that he is seeing something you are not.

Hearing
As with smell, canine hearing trumps human hearing, but with some caveats. It used to be thought that dogs had superhuman hearing. In reality, dogs and humans hear about the same but with a few key differences. Dogs can hear in the ultrasound range, approximately two octaves higher than humans can hear. Thus, dogs can hear some sounds (e.g. a dog whistle) that humans cannot. Evolutionarily, adapting this trait was advantageous for dogs in catching prey. For example, rodents communicate in the upper octaves of sound not usually detected by humans. If a dog was to be successful catching this prey in the wild, it had to develop the ability to hear its dinner.
Furthermore, dogs can detect and localize sound with more accuracy and discrimination than humans. For example, if our dog were to join us in a noisy bar, they would have a far better chance picking out and locating the source of a single voice in the crowd than we would. Understanding canine hearing may help us to understand the cause of a dog’s agitation in some circumstances. She may be hearing something we cannot.

Touch
While the areas of the human body most sensitive to touch are the fingertips, the most sensitive part of the canine body is the muzzle. Dog’s paws are much less sensitive than the human hand, and with good reason. Dogs use their paws to walk. Their mouths, on the other hand, are used much like our hands are—to explore the tactile world.
Interestingly, one of the least sensitive parts of the canine body is the base of the neck, which happens to be the place we use touch to guide and correct behaviors with a collar. This is why you may see dog experts recommending the modified placement of a collar higher up on the neck, as this area is more sensitive. Understanding that the muzzle is the most sensitive area of the dog’s body can also help us to understand the effect of correcting a dog with a firm touch on the nose.

Taste
Taste is the one sense where human ability far surpasses canine capacities. Just take one look at a dog gulping down his food and this would seem to make perfect sense. While a person has approximately 9,000 taste detectors on their tongue, a dog only has about 2,000. Thus, they are able to distinguish between sweet, sour, bitter, and salty, but not with the same degree of discrimination as humans. Dogs also have a strong aversion to bitterness in foods, which explains why products like Bitter Apple help to discourage canine interest. Dogs also are considered neophilic, meaning that they like to try new foods and will likely try nearly anything you put in front of them. Not the same as humans, especially children, who may take decades to ever try a new food. Like peas, or lima beans.
On a medical note, it is important to know that dogs are extremely allergic to some human foods. While most of us know that chocolate is bad for dogs, it is also crucial to know that onions, garlic, grapes, raisins, and coffee can also be very harmful to dogs. Dogs also have different nutritional and caloric needs compared to humans. When you come to train your dog with us, we can discuss your canine’s diet and nutrition, as well as senses, drives, and needs.

Kazi Abdus Sobur
DVM student.
Bangladesh.
kazisobur@gmail.com