That's wildly out of kilter - this data shows humans at only 2.3% of animal biomass, with arthropods holding the largest segment at 39%.

EDIT: my sibling comment mentions CO2 emissions - I agree that your stats look like they're related to CO2 emissions.

That is just for mammals, not all biomass.

I think that's for the causes of CO2 emissions

From figure 1 of the article:

Humans: 0.06 Gt C

Livestock: 0.1 Gt C

Wild mammals: 0.007 Gt C

So humans and livestock make up (0.06+0.1)/(0.06+0.1+0.007)=96% of MAMMALS.

Relevant xkcd: xkcd.com/1338/