Here's another photo that I like from my recent trip to Western Australia, a picture of two Australian sea lions fighting:
Two male sea lions having a friendly discussion
The animal on the left is a juvenile, and the one on the right is a mature bull. Despite appearances, they're not having a serious conflict. They're play-fighting, sort of like the way dogs tussle with one another sometimes.
I'm not 100% certain, but I assume that this type of behaviour is to establish social status, as is common among many other animals.
In this case, the older individual sauntered up to the little one, greeted it, then bullied it a bit. Much to his credit, the little one stood his ground, though he did make a few strategic retreats during the encounter.
As you can see from the image, sea lions kick up a lot of sand and other stuff when they wrestle. This, plus the fact that the sea lions swim extra super-fast when they're playing around, makes it relatively difficult to get clear photographs of such behaviour.