What you are going to watch in this video is a mustang stallion defending his mares and foals from ‘bachelor’ horses.
The main thing in the wild is getting the biggest herd to carry on the genes and if a stallion doesn’t have a herd he’ll “poach”, for example, take mares from existing herds. That’s why the main stallion was keeping the bachelors away, to keep his herd as big as he could. Firstly, they get close to one another not in a submissive way but mainly to size each other up in a mostly non-aggressive way. The bowed, tight necks they show are a threat of power, but the lead stallion is very giving. It is the bachelor that challenges him several times by following him after the lead tries to scare him off and evidently fails. He seems like a good leader protecting his kids from the threat around. Watch the video for more!