Today's XKCD has a rather disturbing graphic showing the total mass of land mammals on Earth divided into humans, our pets and livestock, and everything else. There's not much of everything else.
As the Explain XKCD site points out here, "Per the diagram, there are 358 million tons of humans, 864 million tons of pets and livestock, of which 520 million tons comes from cattle, and 34 million tons of wild animals; for a total of 1.3 billion tons."
Update: The comic now indicates that it's land mammals we're talking about here and not "land animals" more generally.
In percentage terms, our pets and livestock account for nearly 69% of the mass of land mammals and humans for more than 28 percent. All the remaining land mammals -- elephants, lions, monkeys, squirrels, moose, rats, mice, wild bunnies, and so on -- put together weigh less than 3 percent of the total.by