Dogs putting their nose close to another dog’s rear end may seem gross to us, but for dogs it is natural and even important.
A human’s first impression relates to sight, for dogs their first impressions are formed by sniffing.
Anal gland secretions are unique to carnivores and some of the information received includes the other dog’s health status, age, diet, gender, reproductive status, disease, and mood.
Dogs devote around 30 per cent of their brain mass to detection and identification of odours, while humans use only five per cent for olfactory purposes.
Dogs have an additional organ called Jacobson’s organ or the vomeronasal organ.
It is located inside the nasal cavity and opens into the roof of the mouth, behind the upper incisors, it sort of allows dogs to taste and smell, some dogs open their mouths when doing this.
The nerve cells from this organ lead directly to the brain, these nerve cells do not respond to ordinary smells but to a range of substances that may have little odour.
The glands that tell dogs the most about us humans, is around the crotch area and dogs can tell if a person is sad or happy based on hormones and pheromones.
Dogs can tell if a woman is pregnant before tests indicate.
The Jacobson organ operates by trapping and binding proteins and moisture using microvilli (finger like membranes that dramatically increase surface area and function) to absorb compounds.
Once a dog detects pheromones using this organ, signals are rapidly transmitted to their brain and cause an emotional reaction, they do not have to think – it’s all instinctive.
Endogenous produced proteins have been shown to play an important role in chemical signalling in non-carnivore animals like rodents, primates and pigs.
The dog that sniffs another first is generally considered dominate over the one that is getting sniffed.
Some dogs may not want to be sniffed by another and can display body language to indicate that, like blocking their bottoms by turning, sitting or tucking their tails in, or backing up. This behaviour indicates they are feeling threatened or uncomfortable. Additionally, a dog may look away from an approaching dog or stiffen his posture and the best response would be to not force a meeting.
Inviting body language; a high or wagging tail, direct eye contact and no raised hackles indicates a desire to engage in the ancient canine tradition of exchanging vital information about themselves that helps dogs build relationships and navigate in the world around them.
