We're rational, self aware beings. Walk, feed and love your dog and he'll be happy forever. Humans are much more complicated than that, but it doesn't mean that our lives have more meaning. The reason that we feel that we need more is because we have an imagined self importance. Living is the meaning of life, that's it.
"The life of a man is of no greater importance to the universe than that of an oyster." - David Hume