Surely many times you are walking down the street and, when you have come across a bunch of dogs passing each other and sniffing each other's butts, you have asked yourself: why? do dogs smell each other? Although this custom is not very hygienic or pleasant for humans, the answer is more complicated than you think and it involves "chemistry".
If you want to know why dogs sniff each other don't miss this article on our site where we are going to explain the reasons in detail that dogs have to always follow this ritual when they cross paths with others of the same species.
Secret revealed: chemical communication
Although seeing two dogs sniffing each other's anus is not a very comfortable situation for owners, the truth is that this is how dogs gather all the information personal of your other canine companions. From the age, the gender, what they have eaten, the race, or even the state of mind of their namesakes; dogs are able to gather all this data by sniffing each other from behind.
And the fact is that unlike humans, who have a much less advanced sense of smell, man's best friends (as they are often called) have a sense of smell between 10,000 and 100,000 times more developed than us In such a way that, when a dog is sniffing another's butt with his nose, what he is doing is collecting the necessary information to get to know his canine companion better and thus be able to socialize correctly with him. This is called " chemical communication," a term coined by the American Chemical Society (ACS), which discovered that dogs they related and communicated through the chemistry that their bodies give off with odors, just like many animals.
The anal glands and Jacobson's organ
What is the reason that dogs can collect all this information just by smelling the anus of their companions? The answer is the anal glands These sacs or anal glands are two small bags that are located one on each side of the animal's anus and contain all the chemical information of it through the secretions it produces.
In 1975, Dr. George Preti, a chemist at the Monell Chemical Senses Center in the American state of Philadelphia, studied the secretions of the anal glands of coyotes and dogs, and discovered the main chemicals and aromas that composed them. Thus, it turns out that the chemical communication pathway of these animals is a compound formed by trimethylamine and several fatty acids, which allows, through its smell, to know the genetics and their immune status. In this way, each dog gives off a characteristic odor because each one has a specific diet and a different immune and emotional system.
In addition to the sense of smell, dogs (like many other vertebrates, such as snakes) have an auxiliary olfactory system, and it is Jacobson's organ or vomeronasal organ. This member is located between the nose and the mouth of dogs, specifically in the vomer bone, and thanks to its sensory neurons that send the information collected directly to the animal's brain, it is capable of detecting different chemical compounds, generally pheromones. So dogs are specialized to smell the anal glands of their companions and thus be able to recognize their emotions and their physical state
Olfaction and olfactory memory
Dogs' most highly developed sense, as is well known, is smell, which is 10,000 times more sensitive than their sense of taste, for example. Because they are born blind and deaf, newborn puppies already use it because they need to find the mother's nipples by smelling them in order to feed. Once they grow into adults, dogs have 150 to 300 million odor receptive cells (compared to 5 million in humans) and this makes them experts in detecting all kinds of aromas. For this reason, these animals are used as search dogs for people, explosives detection, drug tracking, or even for the detection of diseases in humans. In addition, the sense of smell has a very important function for the reproduction of dogs, and that is when females are in heat, their glands release certain pheromones to let the males know they are receptive.
Apart from being the most highly developed sense, dogs also have a very efficient olfactory memory and they are able to remember the smell of other dogs, even though they haven't seen each other for years, thanks to the fact that they smell each other as a habit whenever they meet again. Their olfactory area reaches 150 cm2, while the area of humans is 5 cm2, so they will always use odors to recognize and remember us and other animals.
