It depends how you count it, whether you include plants etc. Humans are only 0.01% of all biomass, but humans and livestock completely dominate the "mammals" category.

Funnily enough, the livestock population weighs about twice as much as the human population.

Humans and livestock completely dominate not only the "mammals" category, but the entire "terrestrial vertebrates" category.

There are only a few other terrestrial animals of comparable biomass with humans, e.g. ants and termites.