Both wild and domesticated horses are very social animals and live in herds. Clydesdales tend to be quiet and docile. When in groups, they rub and nuzzle one another.
Horses use a wide variety of postures and facial expressions to communicate with each other.
Male horses exhibit the flehmen reaction in response to the scent of a female's urine. This reaction is characterized by a curling of the upper lip, and males exhibit it before breeding. A young male will often take a submissive posture, with its head level to the body and its mouth open, when near an adult male. Stallions will bare their teeth as a threat display. A stallion bares its teeth.