Canine epidermis is much thinner, very regular and even, so the tattoo does not need to penetrate as deeply into the skin. In canines, the tattoo needle does not reach the pain nerve endings, therefore it is not possible for the dog to feel pain. They feel the vibration of the marker, but that is all. It is true that some dogs will initially offer resistance. This is because dogs generally dislike being lifted onto a table and held secure on their side, especially by strangers.
Some dogs also dislike the noise the clippers and tattoo markers make.
Other's have more sensitive tactile senses and they react when the vibrating marker touches their skin. In addition, they are in unusual surroundings and they are nervous. Any of these factors may be enough to make your dog voice his or her displeasure. However, if you remain calm, your dog will stay calm too. Calm reassurance will let her or him know that you are there and that everything is okay.