We think we're so cool, what with our ample free parking and choice of toppings. But look, really the only valid way to determine a species' dominance is to measure its biomass. How much would everyone weigh if we were mushed together and put on an extremely large bathroom scale? Sadly, we have to be content with informed estimates. Together, humans weigh in at about 350 million metric tons. Krill, termites, and cattle all have us beat. And cyanobacteria, those little dudes who triggered the greatest extinction event ever, outweigh us by a factor of three. We're not even contenders.