Sometimes two males will stare at each other and neither will submit. One male will then vocalize. If one male still does not submit, a charge will follow. Bull issues a vocal challenge. Bull charges and others flee.
Most charges are over in just a few seconds.
The males will charge each other. One male often runs away, thus ending the challenge. If he doesn't the two will slam the upper part of their bodies together. They will push and shove each other with their massive weight. Most charges end here with one of the males backing down and running away.