Does it ever seem to you like your dog naturally likes or dislikes certain people he comes in contact with? Well, you’re not crazy- it’s a natural occurrence in all dogs. In fact, the better their sense of smell, the more picky they are with whom they like or dislike.
Emory University used an MRI machine to help prove this theory by looking at the dog’s brain when exposed to the scent of people and dogs that were both familiar and unfamiliar to them. The scent of the dog’s owner activates the pleasure center of the dog’s brain. Dogs were found to prioritize the scent of humans over other scents. Typically when a dog sniffs a person they are uncomfortable with, it’s due to the pheromones that person is giving off. To the dog, those pheromones may signal a threat or an alarm telling the dog to beware. Humans can also give off pheromones that reek of fear or nervousness to a dog.
Dogs have a predisposition of what humans should smell like - when that scent doesn’t add up, the dog naturally raises its alert levels. Wearing strongly scented perfumes or colognes can also trigger this behavior in dogs. The dog is mostly curious as the human he’s coming in contact with smells differently than what’s expected by the dog. It’s always best to give a dog some time to sniff around when coming in contact with new people, places or pets and give them time to figure out all the new scents flooding their nostrils. But it’s not always all about scents, smells and pheromones. Looks, memory and behavior can set off different triggers in dogs.
A few more reasons dogs don't like someone
There is something different with this person that unsettles them. The person may wear a hat, have a beard, talk loudly, be a child, wear baggy clothes, squeaky shoes or rattling jewellery… How to avoid: Make sure your dog gets exposed to lots of different people when they are young. Something reminds the dog of someone they had a negative experience with in the past. Some dogs don't like men, women, kids, babies, fast moving objects, loud objects.
How to avoid
Make sure all the first encounters your dog has are controlled and positive. Don't let the first contact your dog has with a child be a scary one for example; prep the child beforehand and control the situation! The person has a body language which is interpreted as menacing by the dog! Look at how polite dogs approach each other for the first time: Pretending not to care, looking elsewhere, being very casual, taking their time and often approaching sideways, they eventually make contact and exchange a nonchalant: "Waddup."
Now look at how "dog loving" people approach a dog: They stare directly at the dog, moving towards it with open arms, typically in some high-pitched voice, baring teeth in a grin and making lots of squeaky noises. Translate that to a dog doing the same thing and you have the bully of the dog park.