Here you can see some sub-adult males mock-fighting. Their interest in breeding activities starts at age 4, but they aren't considered bulls until after age 9.

At this point they're simply butting necks and not using their sharp teeth. But they're learning technique that will be invaluable later.

Their heads are held high to protect their heads from bites and direct their opponents to their necks. Their necks will thicken from scar tissue developed during battles.

Adult males or bulls stretch high and inflate their large nose or proboscis and created a large bellowing sound. There are breaks in the sound similar to a drum.

Often these displays of size and maturity are enough to scare off any opponents.

Birthing season is still 3 weeks away and the harem configurations are loose. In fact, these are really just immature females come in early.

As pups are born, females will move close to the male for protection.