Battle for Superiority

In response to Jenny Beers's question, "If humans saw themselves far from the superior beings on Earth, what living creature do you think would take our place?"...

     This question is absolutely fascinating, but I do not think that it has one single answer. My immediate thought upon reading this was, what is the creature with the closest levels of intelligence, sentience, memory, communication, and sense of self to ourselves? In other words, who is at the top of the food chain, literally and figuratively? Several animals crossed my mind, from lions to dogs, from dolphins to monkeys. It does not seem without the presence of humans though, that these animals would necessarily dominate to such an extent. What is a very distinct possibility however, is that just as when humans sparsely populated the earth, certain creatures would dominate depending on what climates they resided in. So, instead humans dominating the entire planet, certain whales might dominate in the Arctic, the big cats like lions and cheetahs in Africa, bears in North America and so forth.
     There are so many incredibly intelligent animals on the planet, but why is it that humans so dominant? We do have the ability to think about our own thoughts and analyze our actions after all, but surely out of millions of other creatures, there must be others who can do this as well. Nevertheless, somehow, whether it be biological, evolutionary, or by the influence of a higher power, humans have been graced with the features that have led us to the point we are at today, and though I am human, it still does seem unfair to me that we are seen in so much a higher regard than the other animals. Furthermore, most people even use the term "animalistic" with a negative connotation, forgetting that they themselves are, have been, and always will be animalistic in every sense of the word. Perhaps I am getting worked up over something that can never be changed, but the future is unpredictable, and there may come a day when we encounter more intelligent and therefore greater beings than ourselves. How do you think humans would react if things shifted so that they were no longer the dominant beings of the planet?