You are watching two dogs play with great interest, but why does the scene suddenly become inappropriate? The two dogs start sniffing each other’s anus? Recent foreign studies show that this unbearable-to-watch behavior is dogs collecting information from each other. In other words, this is the dog’s profound skill of identifying another dog by smelling its anus. Do you believe it?

　　First of all, I do not know why those weird foreign researchers would study such things, whether it’s out of sheer boredom or if there is another reason? I also don’t know what kind of sophisticated research methods they used to come to such a conclusion: dogs can obtain complex information such as emotions, gender, diet, etc., by sniffing each other’s rear end. Moreover, a dog’s sense of smell is 10,000 to 100,000 times more sensitive than humans’, so they can clearly distinguish certain specific chemical components in the scent of their kind.

　　Scientists have found that at the end of a dog’s anus there is an area called the anal glands, which release important chemical identification information. One gland is the “apocrine gland,” which releases the dog’s natural scent; the other gland is the “sebaceous gland,” which lubricates and waterproofs the dog’s skin and fur. The main chemical components released from these glands, contributing to the dog’s odor, are various short-chain acids, some resembling trimethylamine.

　　Trimethylamine is an organic compound produced after the decomposition of plant and animal food. This smell is close to that of rotten fish and bad breath. The special odor released from a dog’s rear end is closely related to its food, gender, emotional state, and other factors.

　　When one dog sniffs another, it can collect important detailed information about the other. In addition, a dog’s nose has a second olfactory system called the "Jacobson’s organ," which is used for special chemical communication and not for smelling food aromas. Based on the brain’s nervous system, these olfactory organs can “divide labor” with other organs to smell odors and grasp the chemical characteristics of the sniffed object. Therefore, the next time you see two dogs sniffing each other’s anus, don’t be shocked; this is their first step in greeting each other.

　　Speaking of a dog’s anus, another point not to be missed is: do you know why dogs love to present their rear end toward you? According to foreign pet websites, when dogs show you their back side, it is a sign of trust. Usually, a dog’s front side represents attack and self-defense, but if they are willing to present their most defenseless back to you, it means you are someone they trust. This behavior also means they like you because they feel comfortable, safe, and at ease being close to you. Furthermore, when they turn their backs to us, with their sharp teeth facing outward, besides trust, it also indicates they want to protect us.

　　Finally, regarding dogs’ delicate rear, I must remind everyone to clean the anal glands timely. Before each bath, owners can do the following: first, watch your head and do not get too close to the anal glands. First, lift the dog’s tail up to expose the anus. Second, place your fingers at the four o’clock and eight o’clock positions around the dog’s anus and apply pressure. When you see thick liquid squeezed out, clean it thoroughly and you’re done. (Picture source: Visual China)