Also, some brachycephalic dogs have other anatomical peculiarities that may impede their ability to communicate effectively and thus lead to negative responses from other dogs. For example, French Bulldogs, Pugs, and some English Bulldogs have normally protruding eyes, “pop eyes,” which may be taken by other dogs as a stare or a threat. In addition, Bulldogs, like many brachycephalic breeds, have corkscrew tails which may hamper their ability to signal friendliness with the usual soft, low wags.

Because I get a lot of questions about dogs not liking Boxers I also want to mention the anatomical features of Boxers – aside from their flattened faces – that may make for negative reactions from other dogs. First, the ears of many Boxers have been partially amputated to assume a pointy shape, then taped to stand upright. Ear position is an important aspect of dog body language. Upright ears, especially if tilted at all forward, are part of a complex of body positions that can signal anything from alertness to tension to outright threat. Second, Boxers' natural body carriage is high and often pitched somewhat forward; that tendency is exaggerated if the dog hasn't been taught loose-leash walking and is constantly straining against a tight leash. Such body posture also may signal threat. Finally, Boxers' tails are often amputated along with their ears, and while many Boxers are wigglebutts, a missing tail, like a corkscrew tail, may impede communication.