just like any lifeform in the universe: every single life form is guided by its need to survive facing competition. Animals, plants, everything that is alive fights for its survival at the expense of other lifeforms survival if needed, and only have the choice to either dominate, subdue, cooperate or flee.
Yes, but we care capable of reason as well.
And wiping everything else out will kill us off, not very smart. The main motivation here is greed and the ego
Animals don't try and destroy everything else, they use what they need to survive.