Dogs
6 Fascinating facts about dogs that you probably don’t know — part 1
Dogs are commonly known as “man’s best friends”. For many of us, however, they have become esteemed family members. I’ve always been awed and fascinated by these creatures and often find myself reading about them. So, I thought I would share some of my learnings.
- A wagging tail doesn’t necessarily translate to happiness
A couple of years ago, a friend and I went for a stroll in a small town in Spain. As we passed by a sweet-looking dog, my friend decided to stop to say hello. As he approached (cautiously I might add), the dog started wagging his tail. As most people would do, he took this as a sign of happiness, or approachability at the very least. However, the dog soon made his opinion clear with a sharp bite to my friend’s hand. Subsequently, I started wondering whether the dog was a bit crazy or if a wagging tail could mean something different. It turned out to be the latter.
In actual fact, tail wagging is a complex and integral part of canine communication. Like humans, dogs aren’t born fluent in their language, which is one of the reasons that adult dogs often find puppies annoying. In the first couple of weeks, however, puppies pick up on the tail language. So, what does tail wagging actually mean then? First of all, it’s important to note that different breeds have different tails, with different orientations and movements. Generally speaking, however, there are some rules of thumb. A tail that is extended vertically, with little movement, indicates agitation and alertness. A horizontally extended tail indicates curiosity. When a dog suddenly moves its tail from a neutral position to a vertical position, or curls it in towards the back (think scorpion tail), it is often a sign of aggression. Then there is the tail-tuck, which many of us know, that signifies submission or fear depending on how tucked in it is.
“OK, but that’s not actually wagging,” you might say. So let’s get to wagging… A study conducted by Giorgio Vallortigara in 2007¹, found that the direction of tail wagging is closely linked to emotions, due to emotional lateralization. Movement towards the right is indicative of positive emotions whilst movement towards the left shows negativity. In fact, this phenomenon is exhibited in many other species, such as primates and even humans.
The orientation and speed of tail wagging are also important. Generally, the faster the wag, the more excited the dog is. But remember that a “happy” wag is generally in the horizontal position or lower. A fast vertical wag can be a sign of aggression. A slow wag, on the other hand, can indicate insecurity. There are, of course many other aspects to consider and perhaps I’ll write an article fully dedicated to the topic in the future… For now, let’s move to some other fascinating facts.
2. Dogs have incredible noses (for many reasons)
OK this point is not exactly a ground-breaking discovery. Many of us are aware that dogs have incredible noses. However, I bet many of you are not aware of the extent of their abilities. Based on research that was conducted by the Sensory Research Institute at Florida State University, dogs can smell 10,000 to 100,000 times better than humans. This is pretty difficult to imagine, so to put it into perspective: the average dog is able to detect the equivalent of half a teaspoon of sugar in an olympic-sized swimming pool.
There are a number of reasons why dogs have such an excellent sense of smell. The first is that they have around 300 million scent receptors in their noses (compared to 6 million in the average human). Secondly, canines breathe differently to humans. When a human inhales, all of the air passes to the lungs. On the other hand, when a dog inhales, only about 87–88% of the air passes directly to the lungs. The rest of the air passes to an olfactory sensing area, which comprises of a labyrinth of bony structures called turbinates².
In addition to this, dogs also have an organ, called the Vomeronasal organ, which allows them to detect and differentiate pheromones. As if this was not enough, dogs are also able to smell in 3D (they smell separately with each nostril), can perceive the passage of time by detecting minuscule changes in odor molecule concentration and they can even detect weak thermal radiation thanks, in part, to their wet noses³.
The combination of these, and other factors, allows trained dogs to detect a variety of diseases, such as cancer, narcolepsy and COVID-19 with great accuracy. Dogs can also be trained to search for missing humans, to detect blood at crime scenes or illegal weapons and drugs. My dog (a miniature schnauzer) is currently in training to become a search and rescue dog and I’m often left astounded, not only by her ability to detect smells, but also by her ability to learn to search for different objectives. I have little doubt that we will continue to learn new and astounding facts about the canine’s ability to smell!
3. Dogs sweat differently to humans
Have you ever wondered why your dog’s armpits smell fresh even after a 6km run? Dogs do in fact sweat, however, they sweat differently to humans. Considering that most dogs are covered in fur, it would be highly ineffective for dogs to sweat through pores on their body. Ultimately, the sweat would get caught on their hair, which would hamper the evaporation/cooling process. As such, dogs have sweat glands (called merocrine glands) in places that have little hair, e.g. on the pads of their paws and on their noses. That also explains why you may sometimes see some wet paw prints on a very hot day. On average, however, dogs sweat much less than humans, which isn’t surprising considering the difference in “sweat surface area”. Their main mechanism for controlling body temperature is actually a process called thermoregulation.
Thermoregulation is a process by which mammals control their body temperature, the details of which differ by mammal. For example, the spots on a giraffe’s body are not only for camouflage but also for thermoregulation (but more on that in another post)🦒. Dogs primarily thermoregulate by panting. When they pant, hot air escapes their lungs and moves up the respiratory tract to the mouth. Not only does this allow for heat to escape the body, but the moist tissues of the mouth and tongue also allow for evaporation, which further cools down the dog. The image below gives a nice visual demonstration of this⁴.
Looking at the image, you might be wondering, “What about when the outside temperature is hot?” Well, dogs have an answer for that as well. Remember that complex, labyrinth-like nasal structure that helps dogs smell so well (turbinates)? Well it has another function… As hot air passes through the labyrinth, moisture evaporates from the moist membranes in the turbinates, which helps cool down the tissues of the turbinates as well as the blood in the surrounding capillaries⁴. This, in turn, helps to cool down the brain and the body, even on a hot day.
There is, however, one more tool in a dog’s arsenal, which is something that humans also possess. It’s called vasodilation, and it’s the process of expanding blood vessels. By expanding blood vessels close to the body’s surface, blood can get closer to the surface and cool down before returning to the heart. The process of vasodilation is actually a dog’s second most important mechanism for thermoregulation (after panting).
Initially I planned to write about 6 fascinating facts in 1 article… However, I underestimated how much there is to say about our loyal sidekicks. So I have decided to split this article in 2 — see part 2 here. I’ll leave you with a great quote and one last picture of a dog (can there ever be too many dog pictures?). Until next time 😊
“The dog is a gentleman; I hope to go to his heaven not man’s.”
— Mark Twain
References
- Current Biology|Seeing Left- or Right-Asymmetric Tail Wagging Produces Different Emotional Responses in Dogs|Siniscalchi, M., et al., 2013
- MDPI| Canine Olfaction: Physiology, Behavior, and Possibilities for Practical Applications|Kokocińska-Kusiak, A., et al., 2021
- nature| Dogs can sense weak thermal radiation|Bálint, A., et al., 2020
- Institute of Canine Biology|Brachycephaly: it’s more than just the pretty face | Carol Beuchat, 2015
